FWIW, Boost Mobile has a similar $50 plan to MPCS. Haven't compared features though.
My suspicion is that more than a few of the phone companies will switch to or include a $50 unlimited plan as MPCS eats into their market share.
As for the texting limit, it's not my biggest concern. I think I've sent maybe ten messages since I've had the phone. All of them very, very short.
I have a good friend that refuses to have a cell because he hates to talk to people like that. I mentioned that MPCS basically threw unlimited text/web at you with their service, and he was like "well that's a bit different". MPCS is subconsciously reprogramming America with their "Unlimit yourself" tag, just like MagicJack is with their $20/year phone service.