Was on TMOUS for 10 yrs., limited data, shared minutes, initially because it was the best family plan with no roaming charges for about USD 164/4 lines. Then when TMOUS went "no-contract", I actually paid early termination fees for 2 of the lines to go "no contract" and it was well worth it.
Now there are never overage charges, all unlimited text, talk and data (one line for my wife's iPhone has unlimited high-speed data at extra charge), 4 lines for less than USD 120. When my wife got the installment plan to buy an iPhone 5 last year for an extra 20/mo., our bill went up to a little less than we were paying.
So essentially, beside the aforementioned unlimited upgrades, we got an extra unlocked iPhone 5 for my wife for the same amount we were paying previously and when its paid off in 24 mos., our bill will go down 20/month again.
I sure hope no one buys TMOUS because they will nix these crazy pro-consumer plans in a heartbeat.
Not affiliated with T-Mo in any way except as a happy customer.