I have the Mercur 15c open comb. It's quite a bit lighter than, say, the 34c safety bar, and a very mild razor. I'm not thrilled with it. I'd put in a plug for the Futur adjustable safety bar, but everyone here is probably sick of hearing me gloat about it so I won't mention it.
I also have the 15C it's a very smooth shaving razor but it's so mild that any smoothness is negated by the amount of passes and or strokes needed for effective reduction.
Thank you! I'm pondering buying a short comb and sending it to Delta Echo Razorworks to have a matching "modern" set.
I don't find the comb to be the determining equation in aggression. The O.C. maybe easier to rinse long growth hairs. Maybe the fierce look of the comb deters some or makes them feel that the razor will bite. I find buffing easier with a OC as there is always some residual lather left over for lubrication.
I guess that because I shave every day, I'll never know if an OC really makes a difference with longer whiskers or not. Oh, well. Keep on shavin'!