The Curve is great IMO. Ringtones are completely customizable (MP3 or MIDI) and loadable from your PC (I don't bother with downloading them from my provider at all). Internet usage is good as well, Opera Mini 4 is the best full feature web browser you can get for it. The Blackberry's internal browser is decent, its like other phone's WAP broswers with some extra features.
Call reception is one of the best I've had. Better than my 8100 Pearl I've found.
Only thing to know about it is if you like all the mobile features it allows you to do (IM, Facebook, Internet, etc) get yourself an unlimited data plan. Once you get addicted to crackberry's, there's no going back :P