Yeah - it was so poor on 3G (not enough capacity... and all of it was on 1900MHz in an 850/1900MHz market) ending up with dropped calls R us.
They 'fixed' it in the nick of time, as my contract had expired around the time of 3G 850/second carrier deployment here. I've had little issue since, and even had a 3 1/2 hour conference call on my HTC Tilt.