I am going to give you my opinion, and for those who argue with me, I will not respond. I have been on 92 cruises so far (we are both 56), most with Carnival (because the prices allow me to take additional cruises per year, but I never would have Carnival be my only cruise for the year) as well as RC. We have been on two Carnival ships this year, with that being said, the negatives just keep piling up for us and my other half no longer wants to travel with Carnival and we spoke about all the negatives we experience and I decided he was right and we cancelled the first sailing out of Port Canaveral on the Mardi Gras....I thought the Mardi Gras being their largest newest ship be really nice, but looking at the deck plans and the fact she holds up to 6k people she is going to feel very crowded inside the ship. There is only a small area of main public area and that is the atrium, if you look at the size of it (yes its three levels but it is more just open air space) you see how small it is and what I mean.
Our last two Carnival cruises this year we found they were even more skimpy on the bacon at the breakfast buffet, in fact, we were on long "traffic jams" at LEAST 20 minutes waiting to get through the line and the bacon is the problem and the buffets just aren't set up properly...for instance, the maple syrup is at the end as well as the jelly and such and when people have got their food they take up time using these items, which cause a longer traffic jam for those in back of that person on that line. They really need to put the condiments at another area so that the traffic can flow better.
We found the lunch buffets to be very limited, in fact, even on the Breeze we only had a meat carving on embarkation day, there were no other meat carvings available for the remaining six days and the choices of food are very lacking...surely many will argue because there is guys burgers and such but to be honest guys burgers are full of grease and fat and the fries are so limp and greasy we can't eat that kind of food and the sandwiches, how about I ordered a turkey sandwich to have ONE SLICE of turkey and a tremendous amount of mayo and a soggy piece of lettuce as well as the tomato, sorry it was inedible!! Food is subjective and I prefer eating healthier and having better and more variety in selection available to me and that is what RC does in their buffets...you get alot more variety/selection on RC. Carnival offers the sea day brunch and it is very good.
We found the Breeze at certain points to be traffic on the promenade deck and we have been on all Carnival ships and its just not the same. People above say the food on Carnival is better in the MDR oh my, I am not going to go there...but I have to give you an example, if you get the prime rib you find it to be totally full of fat and not much meat...where on RC you also get prime rib and it is much better and alot less fat. Both cruise lines give enough assortment of appetizers, salads, main courses etc, but the desserts on Carnival are always much better.
Late at night on Carnival you only are able to get pizza (after 11pm) where on RC you know, they have sandwiches, cookies and such available as well as pizza.
Stateroom beddings are both equal, both very good. If you get a balcony room, balconies are much larger on RC.
I totally get and understand the fact your tired of the same decor and that is one of my negatives about RC their ships all tend to look the same....we like to experience variety in decor on our ship to feel like we are on a different ship, the reason why we are booked on the Celebrity Edge for December 15th, we cancelled our October Carnival cruise and my sister/brother in law have taken the transatlantic cruise (Celebrity Edge) that just got back two weeks ago from Rome to Ft. Lauderdale, they loved it so much that they are currently again on the Edge and boarded her yesterday. They took many photos of the food and I tell you, all I can say is WOW and AMAZING!! Grilled steaks, chicken to order in the buffet, a tremendous amount of great food selection and variety, it blew me away, I just can't wait to try Celebrity, so perhaps you consider that too.
Entertainment is always much more of a plus on RC if that is important to you. If your into trivia RC offers it more. Their drink package is unlimited on RC and you have a 15 maximum drink on Carnival. Yes, RC costs more but you get what you pay for.