i live in Fort Worth... worked all over the DFW area. and .. most of the locations are crap speeds.
sure if you are right next to a tower (within 1/2 mile and at non-peak times), you can get good speeds.
but my friend on ATT, I can count on his phone getting the data we need.. so i normally let him do all the data inquires.. or look up videos.. or websites.. or anything that is more data intensive than navigation!
i wish i was exaggerating