I have the unlocked Verizon CDMA KeyOne. Visual voice-mail is the only feature that doesn't work (which doesn't bother me, since I never use it). HD Voice works just fine, as does everything else. And switching over was a breeze - just went to the BYOD section of MyVerizon, entered the EMEI (or whatever) number, followed the directions, and was up an running. I'll admit that I've not tried Wi-Fi calling, but probably won't, as I use other services (Google HangOut, BBM) for VOIP talk and video calling.
Hope that helps.