We were slightly worried about going with Princess after being very happy on our last cruise with Royal Caribbean. We were however very happy with the Emerald Princess.
As with other reviews I would say the entertainment was not as good as Royal Caribbean but we don't really go for the shows so that was not a problem to us.
The ship is beautiful, the staff are very friendly and cannot do enough for you they are constantly asking you if you are okay or if you need anything.