My daughter (now 10) loves being in the kids clubs - whether on
DCL or RCCL (we've been on Freedom & Oasis). She would have no problem spending the entire day in there if we let her.
The biggest difference between the two, however, would be that it is not possible to be in there all day on RCCL. On DCL, they are open continuously from when they open (usually) at 9am through closing time (usually midnight). On RCCL, the kids clubs - Adventure Ocean - has "sessions". The kids club will open at 9am, but then close from 12pm-2pm, reopen 2pm-5pm and then close for another 2 hours, and then reopen from 7pm-2am. However, there is a charge (IIRC...$7 per hour) per child from 10pm-2am (they call that the "late night party zone"). I don't get why they close for those intervals
and it is really troubling for us. If you sleep in a little late, finish breakfast at 11am or so, if the kids go to the club they will have less than an hour. We always have second seating for dinner. So when they are closed from 5-7pm, and we're not going to dinner until 8pm, why should the club be unavailable to the kids for those 2 hours? It's fine if you have first seating and you're going to be at dinner most of those two hours anyway. I guess they just don't hire enough staff to rotate throughout the day with breaks and all. The one big positive for RCCL is that it does remain open later. I wish Oceaneer's on DCL stayed open an hour or two later.
The other big difference is the age breakdowns, as mentioned previously. On DCL, the entire area is for all kids 3-12 years old. On RCCL, there will be separate rooms/areas for 3-5, 6-8, and 9-11. After 10pm, they may put them all in one room - depending how many kids are left in the program.