Which plan is better? Sprint or Tmobile?

For the iphone 5s

In my opinion Sprint is the better of the two. Better overall coverage (=better signal strength),
4glte if available in your area. Currently upgrading their existing and adding cellular towers, etc.
I was locked into a 2yr contract with t-mobile and I could go on and on of how dissatisfied I was.
Currently in the Sprint network and love it!
Best of luck on your decision.

Depends on what area you're in. T-mobile now offers a 7-day test drive program for their network with the iPhone 5S, so I would recommend checking it out at least.

http://explore.t-mobile.com/test-drive-free-trial?icid=WMM_TM_RVR_STKIIK1HFV364