Unless you finance your phone via a third party, except they generally don't have any incentive to offer generous terms like $0 down, no interest...
At least now, consumers will have the choice to purchase the phone elsewhere to receive a lower service fee from ATT or T-Mobile.
Assuming I'm interested in financing the phone, since I have to take a HP for credit check regardless, I mind as well find alternative financing, and pay a lesser service fee. For instance, I can apply for a new American Express card with a $150 sign up bonus, 15 month 0% financing, 1% cashback, and 90 day accidental/theft protection with a 1 year extended warranty.
Or, if I want to buy it outright, I can opt for a CC with a higher signup bonus, and forgo the 0% financing.
The difference now is (1) financing outside of the phone carrier will have better terms, and (2) will result in the lower no-contract price, which had never existed prior to T-Mobile's challenge.
The consumer is better much better off now than a month ago.
PS - Use an AmEx to buy an unlocked phone from Apple, and feel free to change carriers at your discretion. With the new Card Act, even if you close your CC, the balance is never due immediately, and AmEx will have to allow you to continue making minimum payments at the current 0% promo rate. I'd rather have the extra warranty from AmEx (since now it'll insure the full value of my purchase), rather than paying for Apple Care.