My husband and I have cruised on NCL and Princess prior to this Carnival cruise. I guess we were spoiled because we will never, ever sail on Carnival again.
Embarkation: Our group had priority boarding because we were going to a wedding. We were shuffled around between 3 or 4 different employees before we found someone who actually knew what to do. We were issued sign and sail cards and a separate room key. Other cruise lines use one card for both, which is far more convenient. We were able to go to our rooms right away even though we were told we couldn't, so that was nice.
Stateroom: We had an interior cabin, which was fine. My husband said he thought it was slightly larger than the other cruise lines. The bathroom was no bigger though, and was kind of out of date. There was a weird odor coming from the toilet the entire time, and stopped working on 3 separate occasions. I noticed that the public toilets all smelled too, like sewage. It was quite disgusting.