+1 to Shawnz
I have Pandora and Slacker and i have no issues with using 3G and streaming music. Im at work in the middle of a 9 story building surrounded by Steel and concrete and it works just perfectly. BTW i dont have WiFi Access here and 4G is not in Buffalo.
Whats your 3G connection like? Have you tried to get a few speed tests to make sure its not your connection?
Also, Why does this make Sprint Slick? Froyo was Google (Android) OS update. Not sprint. If you want to possibly blame anyone, start with them then go to HTC for layering Sense then you can eventually get to Sprint.
Just something to think about here...