I haven't been on a Princess cruise in many years so I don't know what has changed, but overall it has been my favorite. Lately I have done mainly Carnival cruises because I can drive to the ports and the post covid prices have been amazing. But until 6 or 7 years ago I mainly sailed on Princess (I would have been in my forties at the time.)
A few of the things that I love about Princess are on embarkation day you can eat lunch in the dining room which is so much more relaxing than the buffet after a day or two of traveling and the process of getting on board. I find the entertainment to be more varied on Princess than on Carnival. I've seen some great comedians on Princess that are hilarious without being raunchy. They have a lot of fun games scheduled during the daytime such as majority rules, family feud, etc. On some Princess ships, when the horn blows leaving port, they play The Love Boat theme song on the horn. The food in the dining room is excellent on Princess. A few times a week, they have different desserts they call "chocolate journey" which are incredible!!!!!
My husband and I also enjoy the Oasis class ships on Royal Caribbean. We didn't care for the food as much, but the shows are unique and entertaining. We saw full Broadway type productions of Cats and Mamma Mia, shows similar to Cirque du Soleil, high dive shows, and ice skating shows. We also loved the Central Park area. The one drawback to the Oasis class ships are that there's not a lot of places overlooking the ocean, it is more inward focused, but I recommend trying it at least once.