AT&T

Oh, it's on, now. With T-Mobile dropping its fourth round of "Uncarrier" news next week at CES in Las Vegas, AT&T today fired a salvo of its own — offering up to $450 to current T-Mobile customers who switch. Here's how it works:

Starting today, current T-Mobile customers can trade in their current phone for a gift card worth up to $250. The amount depends on what the phone is, and how old it is. But $250 is the maximum.

And then they can get up to $200 in credit when transferring service to AT&T, activating an AT&T Next plan, buying a new device at full retail price, or activating a device they already own. (A reminder, folks, that AT&T and T-Mobile LTE bands don't fully line up.)

Source: AT&T; More: AT&T Switch site