I've sailed on Princes, RCI, and HAL among others. To me, Princess just does it right, but that is my opinion. Their ships are immaculate, the service is impeccable, and to my tastes the food is wonderful.
The ships do not have all the "glitzy" add-ons that RCI ships do. They have shops, extra fee restaurants, on some ships they have the International Cafe, on most ships the have the Sanctuary and I believe all ships have MUTS (movies under the stars). They have small, medium, large and extra large ships. On some of the ships they have the Sky Walker lounge, deck 14 or 15 (can't remember) all the way aft. They have plenty of dancing and they have piano bars on most of their ships. They have karaoke, and most of the activities of the mass market lines. What they also have is a wonderful ambience. It's not stuffy, but it's not yelling into the PA system 24/7. They have pool games, and it does get a little loud there, but they also have areas where there is peace and quiet.
I honestly don't think you'd regret going on Princess, at all. In fact, you might become hooked like we are