GENERAL:
The nüvi 660/680 are about $730/$1,000, check for latest discount prices (HERE).
They have an operating system and mount similar to the StreetPilot c550, but it is somewhat larger (but lighter) with a 4.3-inch diagonal screen  (480 x 272 pixels), as compared to the c550's 3.5" screen (320 x 240 pixels) and the 7200's 480 x 234.  This screen size seems more ideal for an automotive GPS.  The unit is totally "touch screen" with only a power button.  But this button  will also bring up a quick access to the Volume/Brightness menu or the audio output switch to the FM Transmitter/Internal Speaker menu.  The screen brightness is quite adequate for sunlight driving, but the speakers aren't quite as clear as those in the c550.

They come pre-loaded with City Navigator NT for street-level detail and addresses, plus listings of nearest restaurants, hotels, ATMs, etc., throughout the U.S., Canada and Puerto Rico in 1.87 GB of internal storage.  (There is about 570 MB left for other maps or data.)   But without a CD of the pre-loaded map, one cannot manage their Waypoints and Personal POIs.  In Europe, the nüvi 660 comes with full Western European detailed street map coverage.  Also supported are SD card data.

The units have the new SiRF Star III high-sensitivity GPS receiver and contains an internal re-chargeable battery.  Closing the antenna to the stored position turns the GPS receiver OFF and is then small enough to fit into one's shirt pocket.

Mounting:
The 660 uses the same 12vdc power jack/GTM 20 FM-Traffic-receiver cable as the SP c550, but there is a handy additional quick-disconnect adapter at the end of the cable.  The suction-mount ball joint is hinged and slightly longer than the one for the c550.  The 680 comes with an MSN Direct receiver/ 12vdc power jack.

FM TRAFFIC SERVICES:
There are two FM traffic services.  The TMC (Traffic Message Channel) and MSN Direct.
The 660 package includes a combination GTM 20 TMC-Traffic-receiver/cigarette-lighter adapter cable.
The 680 package includes a combination MSN Direct receiver/cigarette-lighter adapter cable.  However, the 680 is also compatible with the GTM 20 TMC-receiver.

In the Atlanta area, MSN Direct uses more of the traffic monitoring stations than TMC, resulting in a more-detailed
display of changing traffic conditions.  As for "reality", MSN Direct also seems superior.
Even though you register these units in a particular city, they work in any major city that has the service.  We know they work in Atlanta, Memphis, Chattanooga, Nashville, Denver, and San Francisco.  See below for the complete lists.

nüvi 660 Integrated Traffic Receiver*:
A unique feature to the 660 is its integrated traffic capabilities. The unit includes a GTM-20 FM TMC traffic receiver installed in the 12vdc power plug (with lights for Power-on and Traffic reception) which notifies you of traffic, construction, weather delays, and automatically suggests alternative routes.  The traffic receiver comes with a free 3-month free trial subscription (US).  To extend the initial service, visit (HERE).  Subscription cost is $60 per year.
*Traffic services available in select cities are noted (HERE).

nüvi 680 Integrated MSN Direct*:
In addition to integrated traffic capabilities, MSN Direct also provides Weather, Gas Prices, and Movie times.  The GDB50 MSN Direct receiver comes with a free 12-month trial free subscription (US).  To activate, re-activate, or extend the initial service, visit (HERE).   (We had one occasion where the unit indicated the MSN service was "Deactivated" and had to re-activate).  Subscription cost is $50 per year.
*MSN Direct services available in select cities are noted (HERE).

The "Go Home" Feature:
Under "Where To" is an icon "Go Home".  This feature, first noticed in the c550, is very useful.  It allows one to return to a frequently visited place with one touch of the screen.  There is no need to search for or spell the name.  The unit will create a waypoint "HOME" (from two options) the first time you touch the icon.  However, if you want to change the location of Go Home, you must first select HOME from the Favorites list and delete it.  Then one can create a new "Go Home".  (This is not explained very well in the Owner's Manual CD).

Routing:

• Routes are automatically calculated with turn-by-turn instructions from a text-to-speech (TTS) feature which identifies turns by street name.
• Custom road preference allow users to prioritize choice of back roads or major highways.
• Automatic off-route recalculation shows how to get back on track, if you miss a turn or exit.
• A detour function enables routing around traffic problems or road construction.
• One Via is allowed.
• One can pan the Traffic maps by touching and sliding on the screen.

Waypoints:
Waypoints (Favorites) -Uploading from Mapsource to the Unit:
If you have MapSource, upgrade it to at least v. 6.11.5.  Then MapSource can recognize the 660, and any waypoints loaded into a MapSource map can be uploaded to the unit directly without having to go through the .gpx routine.  These Favorites will be ADDED to any favorites in the unit.  By loading "current.gpx" back into MapSource, one can see all the waypoints stored in the unit.

NOTES: Waypoints can't be deleted 'en mass' or by symbol from the Favorites menu.  They must be deleted one at a time with the Favorites Edit function.  However, with a hard reset in the Maintenance mode one can by pressing down on the top left corner of the Nuvi's screen while turning it on.  This brings up the "Pre-Boot Mode".  Keep pressing the left corner until the dialog box comes up asking you if want to go into Maintenance Mode, then press "Yes".  One of the options is "Clear Waypoints".  This will reset the unit back to factory conditions.

The nüvi 660 does not come with any MapSource capability.  One would have to purchase a MapSource map or Trip & Waypoint Manager in order to create, upload, or view waypoints in the unit on a PC map.  We understand Garmin Support will supply a copy of City Navigator NT v8, if one asks for it.  (It probably would cost Garmin all of a dollar extra to include this CD in the package).  European users should back up their .img and .bin files.

Personal POIs:
You can use Garmin's POI Loader (or G7ToWin, which can save waypoint data to .gpx files that can be read by the POI Loader).

Features:

• Unlike the c550, touching the moving map allows one to pan it.
• One can enter a four-digit security code that requires anyone without (or forgets) the code to return to the "Secure Area" to unlock the unit.  Otherwise, it must be returned to Garmin to get it unlocked.
• Avoid Traffic Tie-Ups and Steer clear of traffic with nuvi's integrated traffic receiver. You can receive alerts about traffic tie-ups and road construction that lie ahead on your route.  Touch nuvi's screen to view traffic details or detour around the problem area.
• Wireless FM Audio Transmission will allow you to hear audio, including voice prompts, MP3s, and audio books, through the car's stereo. The FM transmitter (not available in the European model) seems too weak to avoid static.
• The trip computer includes a resettable odometer, timers, average and maximum speeds.
• Bluetooth wireless technology allows hands-free calling capability when paired with your compatible phone.  Just tap the screen to dial or answer a call, then speak into the nüvi 660's built-in microphone.
• In addition, easily look-up and dial numbers from your personalized phone book or from your phone's call history log. Don't know the phone number for your destination? Simply find and dial it from nüvi's extensive points of interest database -including hotels, restaurants, stores, and attractions.
• Travel Kit contains built-in support for travel and enjoyment tools, including: an MP3 player, audio book player (for Audible.com media), JPEG picture viewer, world travel clock with time zones, currency converter, measurement converter, and calculator.
• Additional audio and content support is provided for optional Garmin Travel Guide, Garmin Language Guide and SaversGuide plug-ins (sold separately).
• Antenna: Flip up patch; MCX-type connector for optional external GPS antenna connection.

Sample Screens
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660 Main Menu   ("!" Indicates traffic Info available)        °   Where To    °             Go Home Menu

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    Tools Menu °  Tapping the Sat. Signal-strength bars brings up the GPS page °  Trip computer

Travel Kit
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Travel Kit Menu                 °                           MP3                           °                  Picture Viewer

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World Clock                  °           World Map (Sunlit Areas)        °                      Calculator

Other Screens
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680 Main Menu (Note Temp.)              °      Select an Uploaded Map           °        Uploaded USA Topo Map

Both the 660 and 680 have Traffic Maps
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nüvi 660 (FM Traffic)

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nüvi 680 (MSN Direct)

Physical Size:
4.9"W x 2.9" H x 0.9"D (12.4 x 7.4 x 2.3 cm).  Weight: 6.2 oz. (190 g).  Case: Not waterproof or IPX0. Headphone jack: standard 3.5 mm.  Power Input: 12/24 Vdc.  Usage: 10w.  The battery rundown time was 3 hours and 30 minutes with the backlight set to 50% -somewhat less than 5 hours and 40 minutes for the zumo and 8 hours for the SP c550, probably because this unit is lighter than those units and has a larger screen.

Joe's FAQs:
  1) Does it have a trip computer?  -Yes, by tapping the Map Page lower-left box.
  2) How many waypoints can a user put in?  -500.
  3) Can a user create a waypoint?  -Yes by touching the map either before or after panning.
  4) Is there a MARK key or similar?  -No.
  5) Can the unit do the "traveling salesman problem" solution?  -No, but a 'Where to?' can contain one Via.
  6) Does it have a GPS info screen?  -Yes by touching the Sat. signal strength bars on the main menu page.
  7) Can it display altitude?  -Yes.
  8) Are tracks displayed? -No, it doesn't record, store or display tracks.
  9) Are POIs displayed? -Not on the navigation map; however, they can be seen on a Favorites, Show Map.
10) Are street names pronounced? -Yes.
11) Does it have proximity waypoints to go with the POI loader?   All of the attributes of the POI appear to be supported, including proximity distance, speed, and icons for the POIs loaded.
12) Will it play music?  -The MP3 format for audio is supported.
13) Do you have to press screen buttons on the screen to get to the maps?  -You have to touch the screen at least once.
14) Is there a computer connection? -Yes, USB to upload additional maps, MP3, Custom POIs, Waypoints, and Extras.
15) How do you update the maps when the time comes?  -It appears that you can replace the existing map in Mass Storage.
16) Does it have a Security Code? -Yes.
17) Can you delete all the waypoints at once? -Not easily, see Maintenance.
18) Can you change the waypoint symbol? -Yes.
19) Is it rain proof? -No.
20) Does it have NMEA out? -No
21) Does it have bluetooth? -Yes
22) Does it turn On/0ff when the power from the car goes On/off? -Yes
23) Can routes be stored? -No
24) Does it have a battery? -Yes, internal and rechargeable through the cigarette lighter plug, power module, or USB connection.*

*Procedure for charging the Battery from a USB Connection: Turn the unit off.  Plug in the USB. (That turns the unit on). Turn the unit off before the maps load and before you get the 'computer picture'.  Otherwise, you can't turn the unit off.

Maintenance Mode:
Step 1. Turn your Nuvi unit off, remove any SD cards from the SD card slot and make sure that the unit is not plugged into any computer.
Step 2. Place a fingertip on the upper left hand corner of the touch screen and keep it there while turning the unit on, a prompt should read " Do you really want to start in maintenance mode?"
Step 3. Select the yes button.
Step 4. Enter your PIN if enabled.
Step 5. Main Maintenance Mode screen should have 4 selections:
                        System information
                        View Diagnostics
                       Clear User data
                        Clear Waypoints
Step 6. After some selections the unit should reboot and you check to verify unit after rebooting.

Diagnostics Mode:
Pressing and holding on the Trip Computer Speedometer (above) will bring up nine diagnostic pages.  A few typical ones are shown below.  Looks like these pages might be interesting, if you were receiving FM Traffic or Bluetooth.

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Features We Would like to Have:

• Tracks displayed.
• Delete all waypoints without resetting unit to factory defaults.
• Include a MapSource map DVD of the map included in the unit.
• Allow routes to be uploaded from a PC map.
• Better signal strength to the car radio.

Now don't get lost out there -you all!
-jack yeazel