I was on the Royal Princess this past May for a British Isles cruise.
EXPECT a fabulous cruise with a fantastic crew. The ship is well maintained but remember at her age she shows it.
DON'T EXPECT all the glitz and glamour of new ships. You'll see cracks, toilet seat covers a different color than the toilet, etc.
She is a classic cruising experience. I have sailed on her 3 times and wish I could do so several more before she departs.