When travelling with my mom, we are loyal to Princess, and select cruises based on itinerary. Princess is just the right speed and general atmosphere, excursions, etc. for us. They also have smaller ships, which is nice.
I did RC with my friends for our 40th birthday year, and it was a younger crowd. We also were going to party, not so much escape and visit different/new to us ports. On RC we did the shows, the water slides, etc., which Princess doesn't tend to have comparable offerings for.
Enjoy whichever ship you end up on!