We have sailed on RC but, for us, it comes down to this:
If it wasn't Disney we wouldn't sail. We'd probably go to WDW.
Ha! That's so us, lol. I know, I know...other cruise lines can be great, too, and cheaper, but

My parents actually invited me on a "free" cruise on Carnival with them out of Mobile or Jacksonville, but I'm seriously debating whether it is worth it...(hee).
That being said, I do appreciate the OP's comparison, which was very fair to both lines. That's something that's hard to find in most reviews around here! Seems they are bashing DCL or blinded by DCL love (like me!).