It is all based on location so there isn't a winner of this Vs. thread. Both companies and all companies have weak and strong coverage gaps. I've been with Tmo 4 years and seen the best coverage 2MBs down constant and the worst No connection at home constantly. We moved to different areas and where we live now has constant 3g and 3.5g coverage and it is only about miles from our old house. We had ATT 3g laptop card and it was equally great and horrible depending on where we were.

If it bothers you where you live and you cant take it, then switch to what works in your area. Just know that ATT may give you the same connection issues if you move out of your signal comfort spot.