I just gave my Sprint Mogul to one of my employees and got the ATT Tilt. I have to say ATT network sucks compared to Sprint... drops happen much more on GSM it seems
But the Tilt is clearly better built physically, and performs much much better... especially when it comes to the dial pad... the dial pad on Mogul always sucked... of course dial pad on Tilt could still be better too.
It's nice that I didn't have to do any hacking to get the GPS to work on the Tilt... like I had to on Mogul