MetroPCS Joining the Big Leagues?

I've noticed that recently it seems like MetroPCS has really gained a lot of mindshare. They have ads everywhere and if you mention the name to someone, chances are they'll know who you are talking about. Another plus is that they're not an MVNO; they have their own network with LTE service being rolled out. Do you guys think that the current big four in the US (AT&T, Verizon, Sprint, T-Mobile) may become a big five soon? Or is MetroPCS still considered a small carrier?