I believe I've had the double once, and it was alright. It's not the size of it that bothers me, because i've eaten a 1-pound burger more than one time (thank god for youth and fast metabolisms), but the sauce that they put on it isn't that great. It really just makes me think of a bunch of greasy burgers stacked on top of each other, with greasy bread and then that nasty sauce poured on top of all of it.
Subway, and other wrap/sandwich places are the way to go.