Europe's had LTE for some time, they have Advanced VoLTE - speeds up 72mbps!..
metropcs is actually in the works of building VoLTE which will; increase data speeds, voice over 4g and talk and use data at the same time (browse the web and talk, etc)
yes metropcs cows their speeds for now as they want to maintain the structure..the snapping was supposed to be at the end of dec..but it was pushed back..untapped to 16mbps...that's quick for mobile
5g won't be ready for a bit but sure it will be nice as 4g is pretty epic at high speeds. sometimes clicking on the wrong link..I can't hit the stop "X" fast enough lol