I kind of love this place.
It's a kind of fabulous mash-up between a diner and a fingerlicking falafel joint. I've never tried the burgers here since the Pitas and Dinner plate combos are immeasurably delicious, but the fries are pretty crunchy if you're in the mood for American.
Although evenings can get weirdly busy, they are well staffed and you can be sure to get your order between 5-10 minutes. I agree with Eric about the tables being randomly dirty, however, in their defense Joe's is very busy for a secluded diner and there are plenty of tables to choose from.
On my visits, I've tried the Chicken Shawarma dinner plate ($11, with fries and greek salad) and the Falafel combo ($8, with fries and pop) and the portions are gigantic. The chicken was tender and soft, and my falafel was very fresh. I found that my food was less greasy than your usual diner fare, and much more fresh.
No wonder there's always a line up.