Have yet to try Princess....But my two cents on big bigger and biggest all come down to traffic flow onboard and staffing. Certain big ships do this a lot better than others. I expect all lines now have these issues.
Love the small ships. You get to know the whole ship of people. Haven’t been on one since 2008 but hope to go on another sometime in the future.
We spent two weeks on the Pacific Princess for their 50th anniversary cruise in 2015 when they re-created their original itinerary to Mexico. The entire cast of the Love Boat and Jack Jones were on board. I fell in love with the ship. The service and food were all excellent. We've book 30 days on her for our 20th anniversary in January 2022. It can't come soon enough.