We have only been on one other short cruise (NCL) and are certainly not experts, but for what it's worth on this one:
Pros - Embarkation/Debarkation simple, quick, and painless.
Service and courtesy in all areas of the ship was extaordinary.
Entertainment was excellent. "Shout" was great - lots of energy. Excellent dancers and singers. Guitar player Jerry was a big favorite.
Cons - Fitness center small and always crowded.
Cabin balcony tiny. Couldn't fit two chairs and actually sit out there.
From our experience, preferred NCL but had a great time on both cruises. Having read dozens of reviews before both our cruises, I think except for a nugget of wisdom here and there, cruise reviews are of limited value since they reflect more the attitude of the reviewer rather than an objective evaluation of the cruise. After we returned from our first cruise on NCL, which was in our opinion fabulous, we couldn't believe the negative reviews on the same ship at the same time. Made us wonder if they were really on the same cruise as us.
Cruisers seem to break down into 2 basic groups. The first are people who have a positive attitude, expect to have a great time, roll with the punches, don't sweat the small stuff, and generally always enjoy themselves. The second are people who go through life constantly spoiling for a fight. No transgression, no matter by whom or how trivial, escapes their wrath. All issues are elevated to epic status. In addition, they have paid their money and fully expect to be treated like royalty.
As an example, after two short cruises, we have yet to encounter anyone at all who was less than extremely courteous. Service on both cruises was extraordinary and everyone was very friendly. I think the negative reviewers tend to either be surly and instigate the confrontations themselves or imagine them.
Also, the negative reviewers tend to be very critical of the food and give the impression they expect 5 star dining 24 by 7. I don't get it. Both of our cruises the food was very good and service was great. Wait staff were friendly and we talked with them quite a bit, got to know them. They made the dining very enjoyable and more like eating at a friend's house rather than an impersonal dining experience. What is not to like about that? A couple of times we didn't feel like a sit down dinner and went to the buffet; once again no complaints. Go figure.
In closing, the only advice I would give first time cruisers would be to do your homework ahead of time. Talk to people you know who have been on cruises, read the forums, and there is a wealth of detailed information on the cruise line websites if you take the time to read it. Bottom line was that we had a really good idea before we went regarding how much we were paying, exactly what that got us, what was going to be extra, etc. Once on the ships, no need to freak out because someone tries to take your picture or sell you a drink. No need to fret over built in tips, service charges, or charges for eating other than in the main dining room - it's all known in advance. Once you've decided to go, just enjoy it!