After years of sailing exclusively on RC, we decided to book X for the different itinerary and their reputation for high quality food. Over all, we had a great cruise, enjoyed the ship, ports, entertainment and have booked another X cruise. But I completely agree with OP regarding the main dining room meals and the inconsistency of the drinks. We found the breakfast and lunch in the buffet had a nice selection and were well prepared. Never ate there for dinner, but we did walk through and the offerings looked quite sparse.
The biggest disappointment for us was the Fine Cut Steakhouse. In comparison to Chops on RC it was a letdown. We were seated at the back of the restaurant facing the freight elevator at the busy entrance to the kitchen. I ordered the "Lobster Tail" which consisted of 2 tiny strips of lobster meat on top of a singular piece of lobster ravioli. DW ordered the rib steak, which she shared with me. We found it to be comparable to what we could get at your average land based chain steakhouse. Not worth the extra cost and will not do that again.
To end on a positive note, the Edge is a beautiful and well designed ship. The crew was always pleasant and helpful.
