The Verizon tech swore up and down that my unlocked iphone 6 plus would not work on Verizon and that I needed the "special" verizon model, but the Apple tech assured him it would work, and as soon as the Verizon guy tried it guess what? My unlocked phone worked JUST fine!
It has all the correct bands and then some! (later I even got another Verizon person to actually add my serial number to the database so my phone model now appears in my records WOO HOO!!!)
If I didn't have a grandfathered unlimited at a special price I would be LONG gone!