We make a trip to the Grumpy Troll on our way home from the Dells every year. It is usually really busy by the time we get there with around an hour wait. Is it worth the wait? Yes. Food is great and the beer selection is always top notch. The servers we have had have always been helpful and go above and beyond in spite of probably being really busy. I have never had anything to eat here that I wouldn't order again. Well worth the trip.
Make sure you check out the town when you visit, it is really a cool little town.