What are the differences between the cruise lines?

Holland America is supposed to be a Premium line and Princess is supposed to be a major carrier like Carnival, NCL, etc. I've cruised on NCL, RCL, Carnival, Costa, HAL and Princess. So far, Princess is my favorite. I sailed on the Amsterdam a few years ago, it was a nice cruise, but Princess has kept me coming back because of the service, food, and cleanliness of ships. The Amsterdam was nice, clean, and the service was great, but to me the food on Princess is much better. We've only sailed on the smaller Princess ships, the Sea, Sun, and Dawn, but all of them have been wonderful. The food on the Sea and Dawn was better than on the Sun, but it could have been the chef on board at that particular time. We're going back on the Sun in October. I don't think you'd be disappointed in either line, but my personal preference is Princess. Right now, I book for the itineraries and price. A lot of people book for the ship. It really depends on what your personal preferences are. Enjoy your cruise!!