Tmobile or Metropcs in NYC

I just received my Z30 and I'm trying to decide between the two carriers. I understand that they merged but Metropcs price is $10 cheaper than Tmobile. I have always been with Sprint so I don't know what to expect from both carriers. Feedbacks will be greatly appreciated.

If I had to pick, I would consider who comes out with OS updates most often. Which has wifi calling.
Which has upgrades jumps or allow you to upgrade your phone and how often.
Who has better area coverage.

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10Character.