If you don't mind eating off the DDP, Bistro de Paris is wonderful. We had a relaxing and quiet dinner there the last time we were in WDW, and all of us (including two "foodies") loved it. (Our other two favorites, based on food quality alone, were California Grill and Victoria & Albert's.) Chefs de France, which is on the DDP, is also good, but has a very different atmosphere - light, bright, noisy, as opposed to Bistro, which is darker and more intimate feeling. Chefs has very good food (or did, when I was last there), but I think Bistro has the edge on it. I will say that because of the DDP, we have reservations for our next trip at Chefs.
Never been to Captain Jack's.
As far as the Biergarten goes, I got dragged in years ago expecting to hate it. I'm not generally a fan of buffets or eating at tables with strangers. I don't mean this to sound like damning with faint praise, but my reaction to the Biergarten was that I didn't hate it. I remember the atmosphere being a lot of fun and the food being fine. I would not be opposed to returning at some point, but there are so many places that I really do love to eat or that I want to try in WDW that we're not planning on returning any time soon.