Last 3 yrs with Cingular/T-Mobile in So. Cal hasn't let me down, even with this rumored "network busy" thing. Riverside, LA, and Orange Counties, no problem. In the mountains in San Bernardino Co. might be an issue if you deviate from the highways, major towns and resorts up there. I'm running a unlocked SE T616. Yea I do run into some pockets of no reception, like in class, in movie theaters, and out in the middle of nowhere, but there is no need for a phone in those places.