I like big single combs too, but I don't have any rose-combed breeds so I figured having some RC Leghorns would be neat. I had better focus on what I have for now though, or I will get out of hand. lolI think the single combed ones are prettier, honestly
Especially because people who raise the rose combs get lazy and don't select for a good comb and unlike the smooth d'Anvers comb, that type of rose comb looks kind of awful without diligent selection (part of the problem is the single comb gene is in a lot of those lines and you can telll)
But also I seriously love the regal/flopsy look of the single comb.
However, a d'Anver isn't supposed to look like a flopsy or regal chicken, it's supposed to look like a cute little bird you found in your garden that doesn't quite look like a chicken.