I am a Royal Caribbean Frequent Cruiser and this was my second time on Princess (against 10+ from RCCL and 1 in Carnival) and I have to say that I would describe Princess as a reasonable facsimile for RCCL.
The ship itself is beautiful and well maintained altough the layout was sometimes confusing (at the end of the week, I was kind of lost when moving around the ship) and the signs were misleading sometimes (example: If you go all the way down to deck 5, you can't go all the way from back to front because you ran into CREW only passages, you have to go up one deck then to do that).
The embark/disembark process were smooth, I don't complain with that.
Cabin space was good, closet space was outstanding and it was quiet (except in embark/disembark since it is located near the service elevators).