Here's my two cents. I personally think Princess is better than Royal, please don't hit me Sonny. The ships are immaculate, the food is awesome, the service is impeccable, the itineraries are great, and the prices are extremely competitive with Carnival. We just returned from the Costa Mediterranea. If you want a fun cruise, check Costa out. They certainly aren't on Princess level, I'd say closer to NCL or Carnival, but they are fun and their ships are beautiful. We were on the Emerald Princess last November, she's was an amazing ship. I posted some pictures of both the Mediterranea and the Emerald Princess. Here
is the link if you'd like to look. I really believe you wouldn't be disappointed in Princess. Can't wait to see what your next cruise will be!