Nice GPS. Free traffic can be tricky unless you know how to use it.

Author's Rating:

Pros: Easy to use.  Free lifetime traffic.  Easy to customize with POI's, vehicle icons, voices, etc.

Cons: Traffic info is slow to load if you don't leave it connected to the charger.

The Bottom Line: 
Ease of use and free lifetime traffic.

Author's Review
This is a very nice GPS.  It works well and is easy to use.   I recommend it to anyone who asks me about GPS's.

Things you need to know:
1.  This is a "wierd" model from Garmin.  You won't find the 255WT on their website.  The box is labeled 255WT, but it's marked 255W on the unit itself.  It's basically a 255W with the traffic option built in.

It's very similar to the 265WT, but this model does not have Bluetooth.

2.  If you buy from an auction site, Garmin will not warranty it.  (It can be registered, though.)

3.  You need to register it.  The problem is, it does not come with a USB cable to connect it to your computer.  The cable can be picked up any where like Best Buy, Radio Shack, possibly Wal-Mart, etc. 

Once you've got the cable and the unit connected to your computer, go to my.garmin dot com.  Once registered, click the My Dashboard tab, this will tell you what's available to update.  

You only get one free map update.

To get your free update, you must download the update within 90 days of first use.

4.  One of the biggest advantages of this unit vs. the 255W is the free lifetime traffic.  A lot of GPS's offer traffic information, but charge quite a bit more for that option.  This unit comes with FM Traffic Message Channel (TMC) which it uses to get information broadcast over FM radio frequencies.
Important things to know about the traffic feature on this GPS: 

You must have the GPS connected to your car charger for it to receive the traffic information.

The power cord doubles as the traffic receiver.  It would be nice to be able to see if there's any traffic on your route before leaving.  While a bit annoying, at least it doesn't require an additional antenna.  I have a Sony GPS that requires the power cord, plus an additional antenna to get traffic, so there's cords dangling all over the place.

You do not have to activate the traffic.

It's automatic.  You'll know you're receiving traffic information if you see a little car icon in the upper left portion of the screen.  
At times, my traffic icon is very slow to display...sometimes as much as 10-15 minutes.  I live on the outer edge of the coverage for my area, so that may contribute to the slowness.  What I've found is if I leave it plugged in to the car charger (and the charger also plugged in and receiving power), the traffic icon is always there.
There is MSN Direct traffic available for this unit as well.  It costs extra, but has more features.  But, according to their website, MSN Direct will cease operations on Jan 1, 2012.

5.  Once registered you can go to Garmins website and download customizations like different vehicle icons, voices, etc.  Most custom voices don't speak street names, though.  They simply say, turn left in 200 feet.

You can also download a free program from Garmin that allows you to record your own voice. 

Or, you can use a program to edit the Text to Speech (TTS) file in the unit.  This allows you to keep the factory spoken street names but still change what the unit says.  Simply "google" TTS voice editor, and you'll see the link to download the application.

Another cool site provides many custom vehicle icons for use:
vehiclesforgarminnuvi dot com

6.  You can create/download your own POI's.  This allows you to create a list of custom business, etc, that you want to search on.  An example would be BBQ restaurants, WalGreens, etc.  There's a very nice site where people build these files and you can download for free:
POI-factory dot com.

You can also create your own POI's if you know the street address:
poigenie.co.uk

This is a very handy feature.  The only thing I don't like about it is that the custom POI's are not "imbedded" into the factory POI's, so searching for them requires a few more "clicks", but no big deal.

7.  The suction cup mount will not mount to textured dash boards unless you use the supplied mounting disc.  But that disc has an adhesive backing and is near impossible to remove once you stick it to the dash.  I bought a vent mount off eBay that works great, the GPS is still near eye level and is more out of sight from peering eyes.