Re: MetroPCS
I hadn't heard that they're supporting iPhones. I have an iPhone 4S out of contract, but I pay AT&T only $40, including unlimited data (5GB cap), though. I've used 1GB in the past 10 days. I see Metro has a 500MB cap on their $40 unlimited plan, 2.5GB for $50, their uncapped $60 plan requires you buy a phone from them and they don't look like they're selling iPhones, themselves.
I had MetroPCS for years before I got an iPhone, and lots of my friends still have them. They're prepaid, no contract, no limits, no overage fees. Just make sure you pay your bill before your month ends, or you'll be running to the nearest Metro store to get your phone turned back on. I had my account on auto-pay, but I have some friends who can never be reached at certain times of the month because they're always late. Their customer service sucked, but maybe not more than other carriers. I only had 2G phones, so I don't know how their 3G or LTE is, but I talked to one friend who has LTE and he's happy with it.
I live in the SF Bay Area, they've been here a long time and coverage is pretty good. I had family in Detroit and Florida, which they also cover; I don't know about coverage elsewhere. I think they use partnerships with other carriers in some areas.
Since they're merging with T-Mobile, I don't know what's going to happen to them.