said by MovieLover76: small markets first seems like they are still struggling to get a handle on these upgrades and they don't want to risk the bad press they'd get on a nyc deployment that wasn't up to par.
Thats pretty much what I took from the entire announcement on Sprints LTE deployment form the begining.
Verizon (and ATT to a small extent) went fast and furious with basic LTE deployment in urban areas, were as I see Sprint starting of on LTE advance equipment that has not been proven reliable by any carrier in the US. Sprint Starting off in more smaller less dens areas so if a problem arises it can be handles quicker and without major publicity then in a major metro.
Sometimes when your starting off you have to walk ( maybe even crawl) before you run.