After being on the Mariner of the Seas, and coming back to Princess, You could notice a huge difference in Quality. To begin with, the Service at dinner was excellent. The buffet offered something more than Royal Caribbean Hot Dogs and Hamburgers, there were many choices, and the buffet menu changed daily, so that you weren't eating the same thing each and every lunch. The fresh water pool is always a plus, and we used it quite frequently. The pizza by the pool was a plus, but sometimes the line would get long, but it was worth the wait.
For us, the itinerary change was fine, as we had been to both St Maarten and St Thomas, along with Jamaica and Grand Cayman, so we weren't concerned about that. Also, the ship made sure there were ample shore excursions to choose from at these revised ports.
The entertainment was good, but not great, we saw the princess singers and dancers, the Comedian and the Illusionist, one thing Princess lacks in is they don't really go and get a Headliner as Royal Caribbean does. However, this is not to say the entertainment was bad, it was good, but it wasn't great.