Thanks Goalie,
Here's the scoop on the 2820:
It's the same as the 2720 but adds Bluetooth and XM. While the Anniversary Vision will have the XM receiver installed in the trunk and wired to the controls, you may not need the Garmin's XM receiver unless you want to add the Nav Traffic feature. If so, it requires an add-on fee to your XM subscription and a second antenna (sold separately). The XM Nav Traffic Antenna is large...around 3" in diameter and the easiest place to install it is on the dash. It's not the prettiest thing in the world, but it works fairly well.
When you get your bike, take a moment to connect your GPS to your computer and log onto Garmins website (www.garmin.com) to make sure you have the most recent version of the software and maps. It's my understanding that Garmin will give you one map update free and after that there's a charge for the map updates. But, like other software companies, there's usually a bug fix or two that you'll get with software updates.
If you get the Nav Traffic feature, you'll receive both a visual and an audible notice when you're approaching a traffic tie up. While the visual warnings are fairly useless, the audibles are pretty good. My experience has shown me that it's not instant, not extremely accurate, but does add the ability to automatically re-route you when you're on a GPS route and approach a traffic jam.
One added feature I noticed when I updated my current 2820 is that you can now change the keyboard layout from the standard alphabetical to a QWERTY layout. This makes the data entry go a bit faster (my opinion).
The Garmin's Bluetooth is designed to pair with at cell phone, but I didn't have much success when I tried it. I'll give it another try when the new bike arrives.
Overall, I've been very pleased with the 2820 on the Vision as I'm "directionally challenged." On lazy days, I'll head out to the country and ride for a couple of hours without paying too much attention on where I'm going. When I want to head home, I simply press "home" and follow the directions.
There's a number of additional features and reading the manual is a good thing.