For those that do not know, Simple Mobile is an MVNO using T-Mobile's network. Using a HTC One S and Simple Mobile's $50/mo plan, I regularly pull in speeds of 12Mbps down. It really is a good value, although I wouldn't test the unlimited data. They've been known to get upset about "excessive" usage past 2GB (although now there are some people claim it's been raised to 3GB).
That's kind of silly since it's only $30/mo for unlimited 4G that also works on 3G if you buy it at Walmart. You can actually get speeds of 22Mb if you are near a 4G tower but there aren't too many of them, mostly near T-Mo stores so you'll be on 3G most of the time.