T-Mobile satisfaction?

Thus far I have had an iPhone on every major US carrier save for T-Mo. I'm pretty fed up with Verizon, slow 3G (I have a 4S) and way too expensive. It's the carrier most likely to violate you if you were in prison with them.

Just prior to Verizon, I bought the 4S for Sprint. Terrible decision. Sprint's network is painfully slow and spotty.

AT&T, despite dropping calls, gave me the best experience. 3G was much faster on my 3GS than it is on my Verizon (let alone Sprint) 4S. My hunch was this was due to being a GSM network (and obviously being HSPA+). While my data usage was much less back then, even the original iPhone on EDGE never seemed too bad on AT&T.

I don't think I want to go back to AT&T (because they're the second most likely carrier to violate you if you were in prison with them), but I'm thinking and hoping that maybe T-Mobile can give me a similar experience.It appears they can cover me with 4G at my home and where I work - Good idea or bad idea?

I like where they're positioning themselves, and I really want unlimited data again.

Who here uses an iPhone 5 on T-Mo and how has your experience been? Bonus points if you're in Southern California, like I am.

Thanks!