My DD was a very picky eater when she was younger, and still is somewhat at age 9. We took her to Biergarten at age 3. To our surprise, she ate more there than we had seen her eat at any meal at WDW, and quite possibly more than any meal anywhere. That trip we had a lot of her living on Mickey Head Ice cream bars, and things we bought from Garden Grocer like cereal and grapes because she turned her nose up at WDW's kids chicken nuggets (FYI- the adult chicken strips are much better, but we did not learn that until the end of our trip), along with a lot of other things. At Biergarten, she tried several different things and ate them. I can't recall everything, but I do recall them having Mac and Cheese, Frankfurters, other sausages, Pretzel bread (a big hit), some type of meatball, regular rolls, fruit, roast chicken, mashed potatoes, and I'm almost positive that in the last few years they have also had chicken nuggets.
Dining with kids is always great there, not just for the food, but for the German band and the dance floor where the kids get out and dance during the show. From that first visit, DD has always ranked it as her favorite WDW restaurant, tied with Princess meals. It is a must do every trip for both DD and DH.