Serious question here. Does the recent law that passed that makes carriers unlock your phone in the States make contracts and less upfront costs for devices more desirable?
I'm on the $30 T-Mobile plan and prepaid, but 100 minutes annoys the GF. Every other prepaid plan seems too expensive by comparison. If you want unlimited minutes and 5 GB or more, should you go post-paid?
I think they still have the option of locking the phone if you are on contract or have not paid off the phone. In any case, the market trend has moved decisively towards BYOD plans and more transparent pricing that separates the device and service costs.
I'm also on the TMo $30 plan, but I almost never go over 100 minutes a month. For me, unlimited minutes are a useless feature that gets packed into the service price, and represents pure profit for the carriers.
If you indeed want unlimited minutes, you can go either prepaid or postpaid. But, the base price will be $20-$40 higher.
With T-Mobile, you might want to check into your actual data usage now that they've whitelisted the major music streaming services. My data usage is normally 3-4 GB. But, since T-Mobile removed music streaming from their data caps, my monthly data usage has reduced down to 1-1.5 GB. That bumps things down pretty close to their $50 postpaid plan, if I wanted unlimited calling.