We've been to Marrakesh multiple times, and while we've never had a bad experience, we've certainly had better and worse meals there. The service has always been great, but the last time we were there (two and a half years ago) several of the dishes were very dry (including the chicken bastilla, which had been great the time before.)
I really do like it, and we've got it booked for our next trip in September, but I'm hoping the food is back up to its previous level and our last trip was a fluke.