You can't generalize that broadly - every ship class has different "bests". Go to http://cruiseadvice.org/BestCruiseShipCabins.aspx to find the best cabins on a specific ship. On the Carnival Destiny, my first and last Carnival ship, I suggest that there are no good cabins.
Wow no good cabins that's a very broad statement I can't argue that statement at all only cruised destiny a few times. I have not had the pleasure of visiting every. Cabin. Will rake your word for that one.
I will say Carnival may not be for everyone. It is geared more for the younger party type. I have cruised 4 different cruise lines and Carnival will remain my favorite. Guess even though we are a middle aged couple we are "PARTIERS" ***CruiseAdvice.org*** will break down each ship and give you THEIR opionion of worst and best. Again its all based on opionion and what the person likes.
We like the fun more upbeat party atmosphere. And feel we have found it with CARNIVAL!!! Whatever you choose, JUST CRUISE!!! its the best vacation ever!!
Luckily I'd been on 8 cruises before my first Carnival cruise or I probably would have never cruised again. HAL and Celebrity are our first choices, with RCI and Princess next. Costa was "different" and would sail them again for the right itinerary. Different strokes.
We've cruised on Carnival, RCCL, Celebrity, Princess and NCL (yuck). After having a CC cabin on the Eclipse, I'm sort of spoiled for Celebrity. I don't mind Carnival, some of the newer ships look pretty good. Any "short" cruise is going to be a party boat and living in Michigan, short cruises just aren't worth it for us unless we do a back to back.