We are not major cruisers (this was only our 6th), but neither are we novices, and are happy to report that this was an overall excellent experience and incredible value.
First, the few minor areas that could stand improvement, the most important of which is: upgrade the quality of your coffee, Princess. Another food issue is that hot foods (especially soups) were sometimes barely above lukewarm whereas cold foods (especially cold soups) were usually not nearly cold enough. And the dining room's service was occasionally slow, most often at breakfast and lunch (one reason we usually preferred the Horizon Court buffet dining at those times).
I must also comment negatively on one aspect of the art auction, which I often enjoy going to. But when we receive an invitation in our cabin for an early drawing for art work to be held before the auction starts, and that doesn't happen, I feel lied to and misled. Not a feeling that I think Princess (the owner or sponsor of the auctions) wants me to tale away!
Still, the positives were very good, starting with our Obstructed View cabin, that had as much room, or better use made of the space, than any other ship. Except for the occasional slow food service, the ship's personnel were almost always efficient and friendly. We enjoyed the food, and thought it was almost as good in quality as to what we'd had on our last Princess cruise -- to Alaska in 1999!
One excellent part of the cruise was the varied activities during the day, and the entertainment at night. Especially good were Carlos Oliver (very funny!), Steve Moris (a former Beach Boy who also tells some good jokes), and Lorenzo Clark, a magician/comedian. The big-scale entertainment was standard cruise stuff...not bad, nothing exceptional.
The basic tours at Puerto Vallarta and Mazatlan were reasonable, although with too much time allotted for shopping. In Cabo San Lucas, based mostly on CC reviews, we walked around town and had drinks, after a 45-minute, $10/person, bottom-glass boat tour, which was really all we needed (and a far better value than the equivalent Princess tour). Maybe if we do it again we'd do the whale-watching or the trip to San Jose del Cabo.