One of the great things about Carnival is their consistancy. Shows are great on ALL ships. VROOM is a great show, but better on the bigger ships with the bigger stages. EXTREME COUNTRY has a great en ding. SHOUT is a fun show toon. The "fly-in" entertainers are pretty good for the most part, otherwise Carnival wouldn't spend money flying them in.
Just one man's (maybe two) opinion. Entertainment is in the eye of the entertained. What you like I may not like. So, for the real answer: go to the different venues, decide for yourself whether it is to your liking, or not, and report back to us with your opinion.