Gad is always very busy, so be careful. There is an upstairs sit-down area, but we didn't get to try that. We ordered falafel and hummus in pita, though they also have ful that would be vegan-friendly. At Gad you order first, at the cash register (and be persistent - people will cut in front of you left and right), get your receipt, and take that to the food prep area behind you while they make it on the spot and return it to you. The menu is in Egyptian so I'm not sure what other kind of stuff they offer - if any Arabic readers out there would translate some of it, that would be awesome! But, if you need cheap (and I mean _cheap_) food in a hurry, head to Gad.
Cons: busy, chaotic