I had mixed results about going without an init string ... it worked for a while, then started coughing up 692 and TCP/IP errors on connect.

I finally (like so many others on this thread) put in:

+cgdcont=,"IP","wap.voicestream.com"

And it works like a charm. Depending on where in town (Atlanta) I am, and which laptop I use, I'm getting between 110 and 150 kbps down and 13 and 20 kbps up.

Too sweet.