Best Sunday Brunch for seafood
Haven't been to Reel Club, but Shaw's is pretty good. It doesn't have quantity like most buffets -- it's actually fairly limited. But what it does have is fresh and very nice quality, and frankly for the price a downright steal. Sixteen would be my favorite brunch in Chicago. You can't beat the dining room/view and the seafood (full, cut, king crab legs) were worth the price of admission alone.
I've eaten at Shaw's for their buffet Sunday brunch twice so far this year, once in each location, and it's outstanding. They have terrific breakfast items (thick-cut caramelized bacon, yummmm), terrific seafood items (crabcakes, chilled shrimp and crab), and terrific desserts (creme brulee, pot de creme). I wrote up a detailed report which you can view at www.chow.com/topics/364403#5927944 - the only thing that has changed since then is the price ($48) and they no longer have hot king crab legs, although they still have them cold. This is my favorite brunch buffet.
I have eaten at Reel Club for lunch and dinner and like it a lot, but have not been there for brunch. (I don't even know whether it's a buffet.) It's also worth noting that, since Shaw's and Reel Club are both Lettuce Entertain You restaurants, it's possible they may share ingredient sourcing and/or recipes.