We chose this cruise because of the itinerary, all ports we hadn't been to, price and 3rd & 4th guests $399 and I was told it would be comparable to Celebrity cruise line. We arrived in Copenhagen one day prior to departure. Cabin was as to be expected for inside cabin for four.
Our most recent cruise before Princess was with Celebrity in 2014 and I am comparing to that ship on every point. Decor seems dated, service was okay, but had issues with our room steward. We'd go to breakfast and come back and our room was not made up sometimes even into afternoon (on Celebrity it was always done by our return from breakfast) and we had two instances where he opened our door and we were still sleeping. Had at least two occasions where "clean" towels had long black hairs on them (my hair is neither long or black). Found other housekeeping issues in public restrooms (drains that looked like they backed up but were never cleaned) somewhat revolting and makes you question overall cleanliness of ship.
Food did not impress. Always found something on Celebrity's menu that was appealing and delicious, not on Regal Princess. Take for instance Shrimp Cocktail. Shrimp was limp not like they should be and all food was so-so to weird and unappealing. They did this corney baked Alaska presentation involving fake, plastic baked Alaska and waiters parading around the room. Really? Just skip the presentation. Another thing that was annoying was all the heavy sell "special ship promotions" going on.