Which RCL cruise were you thinking of? The Sovereign of the Seas is the RCL ship sailing out of Port Canaveral.
We've sailed it 3 different times. It was our first experience with cruising and hooked us for life.
The SOS is an older ship but in good shape. The cost is generally much less than the Wonder for the exact same sailing.
Even with that said, we prefer
DCL.
DCL private island is nicer. Though there is nothing wrong with Coco Cay (RCL private island)
I liked the food better on DCL. I sometimes had a harder time finding something that appealed to me on the SOS.
The service is generally better on DCL. Although we had an outstanding server in Sept on SOS.
I would also think about what your kids like. Are they disney kids? There are plenty of teen activities on DCL. My DD was bored on SOS. But in all fairness, her first cruise experience was on the Wonder.
If cost is an issue, SOS is a good cruise. I'd just rather pay more and sail DCL.
Hope that helps.