There's a reason the shows are short...
With that being said, like the food, entertainment is subjective....
But I have to say, I prefer shows on RCCL and NCL more than MSC. Comedy was best on NCL, RCCL and then MSC (in that order).
I have not seen Seascape's entertainment, so I cannot comment, but I wasn't impressed with the Seaside, Seashore or Grandiosa.