Luis,
I absolutely agree with you on that. Location location location! One size does not fit all, if it works in the places that matter the most you, Kudos man!
Sprint works everywhere I need it too, with fantastic coverage, I sit at work with full bars, as everyone else, with VZ, TMO, and ATT sit on 2G with 1 or 2 bars.
I know that if I switched back to T-Mobile, I would be sitting at work, with my phone on edge, even though if I were to walk out of the building, I would probably see 4G.
Everywhere else, T-Mobile was decent, but overall the places I go, I see better coverage and building penetration by Sprint.