We just got back after sailing on 5/29 and it was not a good experience.
Let me start by saying they are not kid-friendly at all. The program they provide for kids is only open with no charge on the days at sea. (that's 3 out of 7 days) The other times (in port) there is a fee for group sitting and you need to reserve it the night before. I wasn't worried about this, since I planned on taking my children with me on excursions, but when they were cancelled due to weather, I wanted to bring my son in and pay the $5 an hour for a few hours at least. No luck, since I hadn't reserved the night before.
Also, the room for the Kids' Club is on the 13th floor and only accessible by stairs via the 12th floor or one elevator from a bank of 4 elevators. It may not sound like a big deal, but when the kids are in the program (which goes from 9-12, 2-5 and 7-10) each time I needed to get them, I had to take an elevator to the 12th floor, get out and wait for the one elevator that goes to the 13th floor and proceed to get my kids. (I had a stroller and could not get up the stairs.) This was annoying to do 3 times a day. The same thing would happen to go to the Venetian restaurant which had the same set-up but between the 6th and 7th floor. (Only 1 elevator would stop at the 6th floor)