We have not been on Seashore, but have been on Seaside and Seascape. MSC ships are beautiful. Since it is an Italian cruise line, there is usually an international passenger base, some of which do not have the etiquette when it comes to the buffet and waiting in line. On a shorter cruise, not sure it would be the same.
The food is at the least, good, in my opinion, portions are smaller in main dining than US ships. The buffet is good, I especially liked the fix your own sub sandwich, and the pizza is usually the best at sea.
We are booked on Magnifica in April, 3 night cruise, which will be our 8th MSc cruise.