As a comparison, T-Mobile's implementation of wifi calling on iOS includes HD audio and handoff to/from wifi/macro networks. Hopefully sprint will be able to support similar functionality soon. Does anyone know if there is something inherent in Sprints implementation of wifi calling which prohibits these two functions?
Reference:
http://www.t-mobile.com/offer/wifi-calling-wifi-extenders.html
T-Mobile is pioneering seamless handover between our LTE network and any available Wi-Fi connection so calls don’t drop between the two. Next-gen Wi-Fi Calling also features HD Voice quality, when calling another HD Voice-capable user. This means our customers can now maintain crystal clear HD Voice calls, whether connected to T-Mobile LTE or Wi-Fi connect – all using their existing T-Mobile number.