There is a line outside the door every day at lunch time. When I walk in, I hear so much Arabic flying back and forth that I think I crept in to a back-alley shawerma stand in Aleppo. Take these things as you will.
I've brought a few people here who were very unimpressed, but that's just because they've spent significant portions of their lives in the Middle East. My obviously-homesick Arabic teachers love this place. You, on the other hand, are probably a white yuppie who can't tell the difference between koshary and mansaf. While the taste is not truly reminiscent of the Arab world, it is about as close as you're going to get in Madison.
In my honest opinion, the falafel is shit, and the chicken shawerma is nothing special. My 4 stars are for the lamb/beef shawerma, which is excellent. Get the lamb/beef shawerma, and only the lamb/beef shawerma.
Portions are also uncharacteristically small for this kind of cuisine. Expect to spend a decent sum in order to get full.
Also, I'd eat here a hell of a lot more often if they actually accepted plastic.