Great post and I have to agree. We are yearly - or every other year cruiser (Live in Canada so its a bigger commitment!) I have cruised both lines and really do not have loyalty to either. I do not cruise enough for "status" to ever become a deciding factor. For me and my family it is more dates (we often cannot be flexible), and ports.
We find the crowds to be very similar - around the pool bar it is louder and more of a party atmosphere - in other areas not at all. We have never seen any type of fights - - however this past New Years on the Celebration we thought there might be a riot!!! I do not know how Carnival didn't realize that the National Football Semi-Finals would be a highly demanded viewing option on the ship, but somehow they missed it. So when a crowd of about 100 angry football fans had no game showing in the sports lounge it got ugly! Carnival was quick to make some phone calls and make it happen! We were cheering for Michigan - but it was the rowdy Georgia fans (who weren't even playing in the first game but knew it meant theirs wouldn't be showing either!) who made it happen. Guest services is right beside the sports bar on the Celebration, so there were some pretty high-ups that were on the scene! It was fun (and never felt unsafe) to watch US college football fans get what they wanted!
I am back on RCL this summer, and it is the first time I have cruised this close together. I am eager to try a new ship for us the Wonder.