I went with a large party of 30--lots of kids.
The waiters and room service people were awesome. And we tipped them well.
However, Carnival is cheap for many reasons. Super tacky decor. Always trying to make money off of you, whether it's interrupting you everywhere you go to take a photo, or shore excursions. Their best price guarantee is worthless, as you must have booked, found a cheaper excursion, and submitted the form 7 days prior to even getting on the boat. (There are definitely the same excursions for half the price!!!) Not only that, but they advertise this best price guarantee while you are on the ship, even though you can't possibly get any money back. I spoke to at least 10 different people about this refund and none of them told me it wasn't possible to get, as I booked our excursions on the cruise. They lied before I booked, as I booked, and after I booked. The first time they mentioned the "7 days prior" rule was three weeks after the cruise, after they directed me to four different emails. Either they are super unorganized or intentionally deceitful.