Hey, cheetah1023! I used to use an Xperia Z long ago -- I totally understand the appeal of these phones.
It looks like this device would be able to take advantage of a lot of the T-Mobile network bands & technologies! I notice that these are all listed as LTE -- did you happen to see a 3G/4G technology list as well? I'd recommend double checking compatibility there also -- LTE is more and more available, but it's still not everywhere!
Also, just for the sake of being cautious, I would recommend taking a look at the Non-T-Mobile phone & software disclaimer and the BYOD T-Mobile data & APN settings -- this is useful info when you're considering bringing your own device!
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