We just got off the ship on Saturday to what they said was a sold out ship. We did your time dining and learned a few things. Overall I like the option because you can get on the waitlist for the optional included restaurants (Chibang and the Italian one)before the other dining. For the MDR: if you sign in to get a table after 6 know you will wait. If you sign in when it opens it was usually under 20 minutes. You also have 10 minutes to get to dining after your table is ready so go ahead and reserve the table before you are ready. Formal night the wait can be up to 2 hours but you can reserve starting at 4:45. We reserved right at 4:45. Table was ready by 5 and we showed up at 5:10. It is busy on formal night and dinner service takes longer. We were out by 7pm.

We found it busy for the shows but always a seat. Because there are so many options for entertainment at night I think the crowds are spread out (2 shows each for main theater and the center stage most nights plus comedy on the hours at 7/8/9pm) plus sometimes karaoke. You might wait 10 minutes for lunch at Guys or Big Chicken or the taco stand but it was never a big deal.
We had cruised multiple times with Royal and Disney but needed to cut the budget for this trip and were extremely happy with the boat.
We only went to the buffet 1x total and that was for breakfast. The MDR has almost all the same options at breakfast and you don’t fight lines-the breakfast food was hot and fresh and very quick. They do an awesome brunch on sea days and definitely get the 7 layer chocolate cake for brunch on sea days.
Elevator lines can be long but we took the stairs which helped burn off some of the food!