Is it better to buy an iPhone 5s from T-Mobile or AT&T?

Which one would be the better deal?
(with unlimited text and internet)

There's no such thing as unlimited internet. You're stuck choosing either 500mb up to 20gigs a month " unlimited " on Tmobile, or from 300mb to 50gigs on At&t. No matter what, if you hit whatever limit you set before months end, your speeds will be throttled with both companies. ( I've been a T-mobile customer for 5 or so years, I have to say their service prices are pretty decent compared to At&t. -- just taking a quick comparison, I can tell you paying $60 a month for 2.5 gigs of data at Tmobile vs 1 gig data plan at $70 at At&t… I'd go with T-mobile just seeing that.) Also prices vary with what kind of plan you're wanting. Contract, or contractless, as well as 16, 32 or 64 gig model of the phone you're wanting.