I've had the Garmin 550c for about six months, and I love it. It has the traffic reroute and update subscription, which rocks. I went with the 550 because of that, and I like having Bluetooth. The range on the Bluetooth is amazing. First time it said "you have a call, do you wish to answer" and the name and number popped up on the screen kind of freaked me out. My husband needed his car worked on, but we'd never been to the place recommended, and he was with the unit in the car ahead of me, I'm behind with my cell, and he said only when he made a light I missed did it say the "unit" was out of range. Screen is VERY clear, changes with daylight and nighttime automatically. Volume options are good, and directions are clear. Battery holds a LONG time. Mine was less than $250 refurbished on ebay.
I didn't look at the Nuvis, but I looked at the Streetpilots (2820 I think?). They're slimmer, but for some reason they don't have an internal battery. While that's not a biggie in the car, it IS if you want to input your routes ahead of time in the house, instead of sitting in your car to do it. For instance, I use it for work, driving to the hotel I'm staying, then the location, then back to the location and home from the location. That's at least three addresses. I like putting them into the unit inside, then being able to call them up in my favs at a moment's notice.
