Good cruise, with the highlight being the Panama Canal. This cruise was full transit so we did not get off the ship in Panama and had quite a few days at sea. If you like to collect small souvenirs you will not get much time at the ports to do so. If you take the aerial tram in Costa Rica there is a shop there. In Aruba there is a place where you can purchase those at the terminal. The one near the ship in Nicaragua is pretty bad, try to go somewhere else and the one in Columbia is a pretty good walk back from the ship so I did not go.
I booked Princess shore excursions on everywhere except Aruba. They were mostly good but a lot depends on your guide. If you book the Jungle Cruises in Costa Rica please be aware that the seats are horrible. I am not sure if this is true for every boat but I was in severe pain the entire time (bad back). In Aruba, there was a woman with a mini-van inside the terminal area that offered us a tour for $25 each. There were 4 couples in the van and it was wonderful! We went the same places as the larger buses and she was a great guide. I'm sure it was some official capacity because most of the taxis,etc. were outside the terminal. There is also a trolley or bus that is right outside the terminal. Friends took it and liked it. There is not that much to see and Aruba is relatively safe. In Cartegena, Columbia many people took a cab to the downtown historic district and I think that would be fine. I would not jump into a cab in Nicaragua and it was about an hour and a half drive to the sites so I recommend the shore excursions.
On another note, I purchased a soda card as I am a bit addicted to Diet Coke. I have done this on other ships. On Celebrity, every time I showed my card it seemed like an imposition to the bartender or waiter. This was not the case on Princess. Show your card and you get service with a smile, not tip required. In the dining room and buffet, no problem.
When purchasing Internet minutes, I suggest you purchase twice as many as you think you are going to need because the connection is very slow.
I also had some concern about the Island Princess as I heard it was going in for an upgrade at the end of this season. I thought it was just fine the way it was.