Does iPhone (4) work better on straight talk or tmobile?

I have iPhone unlocked for tmobile. I'm always getting a bad connection and dropped calls. I'm in Dallas Rockwall Texas area. I'm thinking of using straight talk because I know that they use AT&T and tmobile towers anyone using straight talk with the iPhone currently?

Go with verizon they have a fiber optic network that surpasses all the other major carriers… I have it on 3 of my iphones