I've been playing around with my RAZR V3c from Verizon...
Haven't done much - changed the power-on sound, the power-off sound, and the mini-screen image (when the phone is flipped open).
I have yet to figure out the proper method of uploading ringtones, but I haven't played with it for more than about 20 minutes.
I need to change the power-on and power-off animated GIFs, and figure out how to upload my own wallpapers.
I dig the fact that the cable/power is a simple USB deal, and I can charge off of it. BitPim is a pretty nifty program - I was able to easily put my contacts/phonebook on the phone, without having to dink with the phone keypad.