We have done something like 20 cruises over the years - this was our first time on MSC and we really enjoyed it! We will be back.
Ship size - massive. 20 floors. 5000 passengers, 1500 crew. But the ship is so large, it never really felt that crowded - except in the buffet. Never had a problem getting a lounge chair.
Food - good (not great). Buffet was good but crowded...limited variety especially at breakfast (same things every day...but that is true on most ships). Main dining was good but not great. Fairly small menu - generally one "ethnic/specialty", one chicken, one beef, one fish, one vegetarian. I eat mostly fish, so if I didn't like the fish option - I was pretty much out of luck. MSC was constantly pushing their upscale restaurants but when I'm on a cruise ship, I'm not interested in paying extra for food.