Best iphone 5 service provider?

So I'm thinking of getting an iphone 5, but I'm not sure what service provider to go with. I currently use Virgin Mobile and I don't really like it too much, it's pretty cheap but the service is very spotty. I don't want to sign a contract and I'd like my bill to be under $100 a month. I know with T Mobile you can buy a iphone 5 for $199 plus $21 a month for 24 months and you don't have to sign a contract. But I heard T Mobile doesn't have that good of service. Advice please.

ANYHTING BUT SPRINT Please. I would say AT&T is the best.