I've been to both at least three times and the only one I will continue going back to is Mama Melrose's. We gave 50's the "Three strikes you are out" try and they struck out horribly two out of three times - bad food and really bad service. We go to MM's at least once a trip and have never had bad service or bad food.
Restaurant reviews at WDW are just like restaurant reviews at any place, including chain restaurants like Fridays, Chili's, Olive Garden, etc. in that sometimes they can be good and sometimes they can be bad. I think you should be willing to try either, or both, and then go with what you like.