We have sailed on Princess many times, but this was our first cruise on the Panex class ships. The Island Princess carries about 1900 people and is a really nice size ship to get around on. It is designed for the Panama Canal and Alaska and does its job very well.
The ship is well maintained and the crew is very friendly. We booked an obstructed view room and were very happy with it. It was about 160 sq feet and well laid out, but it was the design with the bed under the window, we prefer the layout with the bed against the cabin wall, but here is no way to tell which configuration you will get from the deck plans.
The food in the dining room ranged from very good to a bit on the bland side. Princess has cut down your options a bit from previous cruises, but there was something for everyone every night. Our chef did an especially good job with the pork dishes. The coffee has improved in the Horizon and the dining room.
The selection in the Horizon Buffet was fine most days. They did try to have a few theme days and that was nice. Still the best Pizza at sea.
The entertainment was the best I have ever seen. the singers and dancers did their jobs very well and the new Bayou show was great.
Getting on and off the ship was a bit more difficult than normal, but I am not sure it was Princess' fault. At embarkation there were just a lot of people at one time trying to get through security. Once inside things went smoothly. Getting off was hampered by it being Veteran's day and apparently a lot of Customs officials were taking the day off.
One thing about the Island Princess that was above and beyond other ships was the Lotus pool area. A really nice retreat to read and use the heated pool!
Overall, I would recommend the Island Princess for a Panama Canal cruise. The 10 day is really nice if you don't want to fly to one coast or the other.