Excellent advice, as always, from Cruise Fanatic. I'd add that another consideration would be the amount of time spent in Bermuda. It's a great place for a family vacation (we've done it four times; our son is 15). Certainly, the ship is a main draw, but when it comes to Bermuda I'd also give a serious nod to the itinerary.
I haven't been on Royal Caribbean in ages, so I can't provide a comparison. Yet I highly endorse Bermuda.