I have only cruised RC one time and it was an older ship. I have cruised Carnival twice with my third coming up this November. For me I didn’t care for RC for a few reasons.
1) Didn’t think the food was as good as Carnival
2) Lack of entertainment
3) The ships set up
4) Price
I am however open to sailing a newer RC ship in the future and would give me a true feel for the RC line in comparison to Carnival.