I think the biggest variable is the distinct feeling of being at sea. It's just wonderful. Also, you unpack once, and your "hotel" moves with you to different ports.
On reviews, you need to read between the lines -- some people will complain about anything.
You will read over and over again here how people take one cruise, and they are hooked. It's the truth. My first was in 2000, and I am now up to nearly 16.
I say give it a try and see how much you enjoy it.