We took the 12 night British Isles trip in June. This is probably my eighth cruise and first on Princess. The good is that the ship was nice, the staff was hard working, the food was always decent to very good with a large and changing selection on the buffet. The pre-destination talks were informative and we caught a couple of art lectures that were very interesting.
That said, the activities and entertainment were all but non-existent. This was the British Isles so, no surprise, it was overcast or raining literally 100% of our trip. Because of the weather, the pools were permanently closed and the decks were windy and cold so, unlike other cruises, you couldn't just go sit by the pool. Seriously, there was almost nothing to do on the ship but eat and watch TV in our rooms which made for a boring vacation. Rarely did we see something we were interested in on the schedule (lots of sales pitches masquerading as entertainment). The three dancing/singing shows we saw were good but there were only three, hour long shows in twelve nights. My teens and I went to the Teen Club and the person running it made it clear they were there for baby sitting and there was zero actual activities for teens. It was the "Not Fun" Ship.
For example, we expected to see the White Cliffs of Dover on this trip since we were going by them anyway (like we saw the Ne Pali coast on our Hawaii cruise). But if we did sail by them, nobody told us and we never saw them. In fact, we sailed by interesting looking coastlines regularly but, unlike other cruises, we were never told what we were seeing and couldn't even find out if we wanted to as the Internet fees were astronomical and the ship board map on the TV in the rooms showing where the ship was at that time didn't work. This would have been so easy for Princess to do, cost them nothing extra, and would have been a big enhancement to this dull cruise.