Carlos, if Ruben still wants an explanation as to why I believe C-Ciel is a stronger pick then F-Ciel, just copy and paste this:
It's all in the neutral game imo. C can fight effectively at ranges that F can't, specifically long range. F's knife set covers some very good angles and can be done as stand alone attacks, but the thing is, C has them too although it is somewhat different. This is probably going to be the deal breaker though: 236C (EX Halo). As sad as that sounds, it's the truth. This one attack only costs 100% meter, and there's just too many things to say about it. Even after all the tweaking it has received, it's still one of the best moves in the game. As I like to say it, it's the kind of move only a KOF boss would have, only differences are they would have a version that comes out in 1 frame, recovers instantly, and guard breaks. But that's besides the point. This move can be a game changer as it totally shuts down other zoning characters. Those characters have to play at your pace and have to respect you at range when you have meter. Going back to the knife set between C and F, C can combo off its knife set with 100% with both 236C (if you're at full screen) AND 623C (not as far). These moves allow C to score damage and close the distance at a range where F can't. There's also the Moon specific mechanics that come into play as well like having access to dodge and being able to sit on 200% meter for a really long time but it's still debatable. C can techically fight any matchup and not be any worse off than F. F will struggle against zoners and characters with superior space control like C-Mech and F-Hime for example. C does not have to worry about this. C can not only fight back against their zoning games but 236C will shut them down. F-Hime has her own 236C which makes the matchup a bit more manageable but it's still a tough match for her. I haven't seen a single matchup where F is the far superior pick to use over C.
tl;dr version: 236C is the deal breaker. I'm sure anyone can get the jist of that and everything else will fall into place.