In my corner of New Mexico...
I work for state government and travel all over. So I use a lot of my 4G service when I can. We have very spotty service here in New Mexico to date. However, here are my results...
Santa Fe
BEST TEST: 9mb down/2 mb up
AVERAGE TEST: 6.5mb down/1.25mb up
Albuquerque
BEST TEST: 7.5mb down/1.5mb up
AVERAGE TEST: 4.5mb down/1mb up
Las Vegas (NM)
BEST TEST: 1.5mb down/1.5mb up
AVERAGE TEST: 1mb down/900k up
These were taken using the Speed Test Labs app on my HTC EVO. Latency has been in the 150ms to 500ms range. Quite a big spread.
Sprint/Clear 4G is very new in our area. I believe that usage is still quite low and may account for our higher than average speeds. I have yet to test speeds in Farmington, Carlsbad, Alamogordo or Las Cruces.
I think the reason why it was slow in Las Vegas, New Mexico was the speed of the backhaul service was limited. I don't think it was because they had a lot of users burdening the system. The town only has 10,000 people.