My Wife and I travelled on the Diamond Princess from Sydney to Beijing in March 13 which was our 2nd cruise with Princess after previously cruising with Royal Caribbean and Holland America. Following experiences with these three cruise liners we would consider that Royal Caribbean to be the better cruise company. Our reasons are as follows:
Rooms -
Little to chose from although the Diamond princess looks a little dated in its decor; needs updating although not a problem.
Good size cabin in quite location on the port side. The extra space in the mini suite was something we liked especially having the couch. Good size balcony allowed us to sit out and enjoy the sunshine as an alternative to the public areas. Also being located in the middle of the ship made it a better place on the one day when we went through rough seas.