You've got your show locations mixed up.
Both MGM Grand and Mandalay Bay have good choices.
At MGM Grand I like L'Atelier, Nobhill, Craftsteak, and Fiamma.
At MB, I like Areole and Strip Steak.
We did Strip Steak before Lion King earlier this year. We did the pre-theater menu which was good but not great.
Have heard good things about RM Seafood.