We picked 2 MSC back to back cruises as the itinieries suited our first trip to the Greece/Italy.
To begin with we were very happy with our booking but at about 4 weeks before the trip I realised they'd changed one of our cabins without telling us, we'd originally booked 12months out so we could have aft balconies, despite contacting the Australian office repeatedly and them trying hard to have our cabin reinstated we were given a mid ship cabin on the first cruise which certainly took the shine off from our perspective.
Boarding in Venice was a breeze, no line ups, our room was ready within 2 hours of boarding and our bags delivered promptly. We had been on the Orchestra previously so received priority boarding, the lineups if you didn't looked daunting.