I had a thorough education in MSC this week. I will say that from what I have heard MSC had its growing pains that most people who know agree that they have really gotten their act together.
The cruise I was one was a quality cruise in almost all respects and comparable to any cruise line, so the answer is "no" it is not that bad.
The whole point is that it is a European cruise line, especially in Europe. If you go there ready to embrace that experience you will have a good time.The food is mostly very good, especially the buffets. The entertainment is good and the cabins are very comfortable.
The service is very friendly, not cold or unqualified as may have said.
Considering kids sail free all year round, up to age 17, if you have a family some of these cruises are a steal.
In the Caribbean the policies change to become more American-friendly, but the ship does not change. You still get modern Europe in terms of food and service. Accept it for what it is and enjoy the difference. For experienced cruisers (who know how to cruise) there should be no problems enjoying this line.