I've been to Meatheads twice since they opened. The first time I had their basic 1/3 lb cheeseburger with all the trimmings ("grilled" onion, lettuce, tomato, mayo, ketchup, and pickles). I also shared a mocha shake. The food arrived fast and the burger was great, except I was certain they made a mistake since the onion on my burger was raw (still crunchy and spicy). Still a good, but greasy burger. The shake was the real star; it tasted like it was made with fresh coffee.
My second visit I got the same with the addition of fries. The total was about $12, so it's not the cheapest burger joint in town. Biting into my burger I got the same raw onion taste. So, it seems to me they heat the onions on the grill, but don't actually grill them; it was still white. The second go at the mocha shake was just as good as the first with an intense coffee flavor. The small order of fries was huge, and probably more than I should have eaten.
As others have said, parking is a mess. The restaurant probably has twice as many tables as parking spaces.