My wife and I are in our early 40's and have sailed on Carnival and NCL. Our best sailing experience was NCL, but we thought we would try Princess.
Embarkation: Wow, Princess has this mastered. Carnival always greeted us with long lines which moved at a snails pace. All the different booths based on your cabin location made check-in a breeze.
Room: We selected a obstructed view cabin and were issued L104, which in many regards was a fantastic room. It had a huge mirrored window overlooking the bow of the ship. There was a decent sized deck in front which we could see, but the mirrored glass prevented others from seeing in. The only drawback was that there was an access door for the public right next to our room. When people when out the door to view the front deck, the door slammed so hard it shook the bed - no joke. At times people were in and out non-stop, but it was only during the day between 9am and 5pm. If we wanted to take a nap it was tough. They close access to the deck at night. We were directly under the treadmills from the gym above and only once or twice heard the thuds of people working off the extra helpings of food. Our steward, Richard, was fantastic and very friendly and efficient.
Food: The food was decent. We were not blown away and the food was on-par with NCL or Carnival. We did the anytime dinner since we eat around 6:00 and had no issues getting a table right away. We some some great people during dinner, but also had a table for 2 on two nights with no wait. The dinner staff was hit or miss. Twice we had very good service and twice our staff was seldom seen and dinner dragged out to 90-120 minutes. Not horribly bad since we met others, but it was a long time. We also had the fish & chips at the wheelhouse for lunch once and it was really good.
Overall service: This is where we felt Princess fell flat. The wait staff in the Horizons buffet area were nearly zombies walking around trying as hard as possible not to make eye contact so they didn't have to assist you with anything. They were mostly there to provide refreshments and refills and keep the tables cleaned. There were a decent amount of staff in the area and most times getting a refill or was impossible. Like I said, they walked around with a blank stare would not greet anyone and just looked tired and worn out. Even the deck attendants were decent, but on Carnival or NCL, they were polite would greet people and seem to enjoy what they were doing. Not here on Princess. During the mornings we would be almost worn out from returning pleasant "good mornings" and bright smiles to the Carnival and NCL staff - from the custodial staff to the deck attendants - it was a very nice touch and was sorely missing from Princess. To me, this was the biggest negative we found.
Selling: This also rubbed us the wrong way. The entire first day and the subsequent morning/ afternoon on the ship was fending off sales pitches for the unlimited soda program and the wine tasting. As stated above we were not impressed with the service of the staff, but were caught off-guard several times the first day when a polite person would stop to say "welcome to Princess!! We are happy to have you aboard, you should check out our wine tasting/ soda card/ art auction, etc." and go into a canned pitch. It was more than disingenuous since we learned quickly that the only person who smiled and and greeted us were people trying to sell us something. Even into the next day, the wine tasting was heavily sold. During the days were were getting into a port, the sales were $4 bottles of water, every corner we turned was someone greeting us with a smile and offer to buy water. It would have been nice to have someone greet us without following it up with a sales pitch.
Spaces: We really liked Vines. Lawrence was fantastic and a truly nice guy. We ordered a bottle of wine and received the complimentary sushi and tapa platters. We could also overhear the music from the main atrium.
Sanctuary: Since we heard such great comments we went there about 10 minutes after boarding and reserved 2 spaces for the week - I am 90% sure we were the second group to book. My wife loves the sun and I prefer the shade, but there is no way to split chairs and be together. It would be fantastic if they could rig some sort of umbrella/cabana top or ? to provide shade to those who requested it. The first two days it was so windy it was impractical to to sit out side. It was just windy and a chilly. The area has about 7-10 community seats that you can use under the shade if you don't want to sit in your assigned lounge. This was great since it blocked the wind, but the wind traveling through the mesh roof material that covers the entire shaded portion made a wicked, loud noise that was almost deafening. The service was good there, but based on the times we used it, it was not nearly worth it. We will never book this area again.
Entertainment: We liked East Coast Connection, but as someone else mentioned why a rock back with no "island" music for the pool area? Also, their set list was pretty thin - we heard many songs repeated over and over. Lastly, since we were in our early 40's the music was a bit out of our preference - however the people in their 50's-60's were all singing along and enjoying themselves. An "island music" band would really have been nice. The comedians were pretty good.