We sailed on the Ruby Princess in September 2010 from Venice and enjoyed the cruise and ship, there was one big problem - where our cabin was located. When we found out the cabin number, we checked the deck plans and found a blank space above the cabin. We mistakenly assumed it was a storage area or equipment room. It turned out to be the galley and the banging and noise from above us started in the middle of the night and made it impossible to get a good night's sleep. We complained several times to the purser but it didn't do much good. One of the people at the purser's desk did let it slip that Princess knows which ones are the noisy cabins, but books them anyway. This was obvious because Princess offered us a $400 credit for our inconvenience. Lesson learned. Never, never book a cabin under an empty space or any of the public areas, including restaurants, theaters, bars, pools, etc. You will be sorry. If you do get stuck with a noisy cabin, complain often and loudly and maybe the cruise line will offer you some sort of compensation.
I also noticed that the new Princess ships have smaller cabins. The older ships had more space per passenger. We always used to like Princess because they didn't try to cram as many people on the same size ship as some of the other lines, but not any more.
One more observation. If you are taking a cruise with a lot of ports you have never seen before, don't bother paying the extra money for a balcony. You won't have time to use it. Oh, and be aware Princess is now charging $3 to deliver your room service order -- it used to be free. What next, a charge for food!