Bought contract-free T-Mobile online and works fine on Verizon.
Really? That's great to hear.
I had been concerned that the T-Mobile 6s (I realize it's the same model for Verizon, T-Mobile, and Sprint) would not be whitelisted for Verizon. I am on Selectel, a prepaid MVNO that uses Verizon towers and requires the phones to be whitelisted by Verizon.