I have previously sailed on Carnival and Celebrity. Had a porthole on Carnival and a Balcony on Celebrity.
We arrived at the Port of Miami on a coach and was literally yelled at by the luggage porter for not having tags. Our tour operator told us we would receive them at the port. I guess it was too much work to get them out of his pocket and write our cabin numbers on them. Nevertheless we tipped excessively to make sure our bags would be properly handled. Not MSC's fault but still a very poor first interaction.
-BOARDING
You must insert you room key into the slot to provide room power. The closet is awkwardly placed in the entrance so the entry door and bathroom door all open into the same area. You have to turn on all the lights in the cabin to see in the closet. Otherwise similar in size and layout to Celebbrity.