I have no problems with streaming, and I never turn my phone off.

My streaming is done from my own broadcast though.

Perhaps you should ping the site when it is working well and ping the site when it is working poorly and see if it is Network congestion.

I listen to my stream over ATT GPRS, how about that one! It is clear and stable. I have the encoding rate low, because I am only streaming voice off my DirecTV. I think I'm only streaming 12 or 16 kbps.

The other thing to look at is if there is an issue with the Processor at the time you have the issue. Perhaps another process is playing with you?

I had no streaming issues in any of the OS versions. I listen to my stream for hours at a time streaming over FMTx to my car stereo.