I just ate there two weeks ago and the food and service were really good. The atmosphere is very neat, unique. We were there on a hot day and really appreciated cooling off and surprisingly it was quiet inside. I think people watch the clips and chat more softly than normal. It is like an attraction with food sort of.
I agree you could easily each get a milkshake and share something. I had the turkey sand on multigrain bread with avacado mayo, it was huge. DH had a mushroom burger, also big. We both got the cucumber salad and liked it (felt too hot to eat fries). We didn't do shakes, I had ice tea and DH had a vanilla coke that was yummy.
I saw in front of us a pasta dish and a steak, hmmm... maybe the negative reviews come from trying to order the more dinner like entrees. Stick with burgers and sandwiches.