I just switched from Virgin Mobile's $35/Mo plan to Metro's $55/Mo plan. I did this because I wanted a phone upgrade to at least Dual Core Android, and I also wanted Visual Voicemail, which only MetroPCS provided for pre-paid no-contract customers.
T-Mobile had a very tempting pre-paid offer: $50/Mo pre-paid, with few meaningful caps, a better network and some very neat phones to choose from. However, they had disabled their Visual Voicemail for pre-paid customers, which totally sucked. They also didn't have any enticing phones at reasonable prices. Metro had the LG Motion 4g for under $150, but T-Mobile's 'decent' phones were far more, in the $250 or more range. I wanted the Lumia 710, but just couldn't justify the price.
So far, I am VERY happy with my Motion. Very snappy, very good battery life, and I got the Visual Voicemail I so craved. Their 4G network works just fine for me in Metro Detroit, and their service has been just fine.
I am even thinking of switching my wife from a grandfathered Sprint Family plan for her feature phone to MetroPCS just so I can get the Motion 4G for her too...