Yes we like Princess a lot. We never cruise Disney when school is out. Never go to Walt Disney World when school is out either for that matter. When you cruise Disney in the off season the prices are much more "normal."
We are a childfree couple and like to cruise Disney. I've done a lot of lines and I've found Disney to be among the best at keeping kids away from adult areas. If you are cruising as an adult couple, you won't have to eat with kids either - you will get placed with other childfree adults.