I've been there late at night when virtually no one else is there and had a long wait for the food. Not the fault of the server, who was very attentive (why wouldn't she have been, the place was empty), but even still, she was very nice and apologetic about the wait, which was the worst part of the experience.
Food was decent. Better than most fast food for a cheap price, but compared to top quality burgers, they are exceedingly average. The shake I had melted absurdly quickly to the point it began leaking over the cup.
Average experience on the whole, though I'll likely go again.