I have 2 cruises under the belt and will be on the 3rd cruise in Jan 2016.
I travel with my wife and another couple.
My last experience on the MSC Opera was very pleasant except for the lack of waiters in the lounges. Sometimes only one waiter.
I would say the cruise on the MSC Symphonia was the better cruise. Better service, entertainment and a better selection of food.
We will be travelling on the revamped MSC Symphonia this next cruise :-)