The ship is very big, so be ready to walk, however, it's incredible, with delicious foods for all tastes, comfortable cabins, an excellent service, with some entertainment (but not always), activities such as videogames, F1 simulator, football ("soccer", for some), baskteball fields etc. The ports in Brazil are very direct to your ship, but I can't give a review on shore excursions by MSC because ...
I have just read reviews of Splendida in November 2015 - very similar reviews.
I do agree, however, that the embarkation in Barcelona left a lot to be desired. It was not organised at all and, unfortunately, no one person appeared to be in control and knew what was happening. I understand there was a problem with check-in computers and shortage of staff - no excuse MSC MUST get this sorted ...