S4GRU.com is a far more useful site for this. Tons of information, become a member and check the maps! There are discussions for each market, and a lot of people contribute great info about when new towers go live and where they're located.
Sponsors (small donation) even have access to maps that show individual tower locations, and it shows whether or not they have been upgraded. (3G, 3G + 800Mhz, LTE, In Progress)
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Once LTE goes live on the 800Mhz band, indoor penetration should be much improved. That will most likely be a 2014 thing, though. For now, I'm loving 1900Mhz LTE.