I just have a tmo 200mb free for life sim set up in USVerizon tab S, I do not know about calling as it has no minutes
tmobile speeds are pretty good where I'm at To new to post link but 44 mb down 11 mb up
using apn fast.tmobile.com
I replaced my Note 2 with a Tab S 10.5. I'll never buy another phone and I'll never buy another Samsung. The battery is not a concern. Treat it right and you'll never have a reason to remove it. That being said, it absolutely is replaceable. Not easily and not without proper tools but you can replace the battery.
While this particular tablet does not have the phone app, the hangouts dialer works just fine.
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