If so, what are the benefits of such a service?
Not at the moment, it may just be a firmware update. Metro has VoLTE service, but its only somewhere in Texas at the moment. The only phone that has it is the Connect and the soon coming Admire 4G
Benefit: clearer calls, less need to rely on CDMA radio for calling. When Tmo shuts off the CDMA network next year, maybe all phones will have VoLTE. At least this is how I understand it.
CDMA wont be shut of until 2015. next year will be when metro customers will have metro branded phones on tmobile's network.
You never know where else has VoLTE if they want to finish the rollout by march next year they probably have to have more areas than that. Remember they said you will never know if your phone is running VoLTE or CDMA it will be very discrete
I seen something about that on G4 TV, they said vm will rollout first in all major cities ny, dallas, la, etc...
If you mean vm as in virgin mobile they don't even have LTE so how would they roll out voice over it