Is switching to T-Mobile a good idea?

A tech savvy people out there? I plan to buy the Nexus Google phone. It’s $ 529 (gay) for one and unlocked for $ 179 with a provider T-Mobile. I was doing an unlocked one until I saw that the plan T-Mobile is only $ 79. At 99 months, while I pay $ 115 with AT & T for the system équivalent.Mais is the move to T-Mobile a good idea? I have no experience with it, but AT & T has many dead spots in my area and I want to say much, if I had the intention to find a way out. All users of T-Mobile has received an opinion? If you do not know what the Nexus One is, you can see here: https: / / www. google. Phone / com / click? locale = en & S7E = I have a 3G iPhone (1st Gen) and Nexus meet my needs workaholic: D