On another note:
Some people seem to believe that F-ciel is "the ciel without 7th heaven". This notion would imply that F-ciel is to be played in the same manner as her crescent form, minus the option to use 7th, when this is far from the case. F-ciel mechanics and design completely contrast that of the Crescent and Half forms. If anything, the C & H forms have more similarities in concepts like spacing, pressure, strings, strategy and objectives than F has to either of the two. If we examine some of the core aspects of the C & F forms we can see just how different the two styles are as well as strengths and weaknesses posed in matchups:
General Spacing @ mid to long range
C (214B>4A)
IMO crescent does appear to have the upperhand in the distanced/zoning game. This knife set is fast and covers a very awkward angle. It keeps opponents pinned down and can be staggered into the final set (which leads to ex followups). Proper use makes this versatile zoning tool hard to get around.
F (214B>214C)
This knife set is probably strongest at 3/4 stage range and will cover a lot of area above ciel. Completing the set will keep a ground approach in check. IMO it's a bit easier to misplace and misuse this set. However, due to the decreased recovery on 214C in CC, I feel players may get more leeway and opportunities to play a bit more reckless with zoning.
F (214A)
A decent ground projectile in Ver.A/console, perhaps gdlk even in CC due to increased speed. I like F's 214A over C's any day: forced down, launches, easily confirmable into EX sycher for added dmg at long ranges. In strings though C's 214[A], although a bit gimmicky, may be a bit stronger.
C (dash 2a, double jumps, IADs)
From the looks of it, C doesn't seem to have much of a mid-ranged gameplan. It seems to be nothing but dashing within 2a range to start pressure or use of double jumps and IADs to close in. IMO C's seems to only be able to transition from fullscreen zoning to zero-range pressure (and vice versa) without any in-between. Because of this if feel that C is lacking in a bit more in neutral and has to take more risks when attempting to approach.
F (dash 2B, neutral 2B, 236B)
I've yet to see any F user throw 2B fishing into their neutral game (even the all-mighty TSA!). 2B has good speed for it's attack range, hits low, can be canceled from and has very little recovery to punish on reaction to whiff or with IADs. From my experience, 2B seems effective in thwarting off aggressive ground approach, i.e. mindless dashing, and will force players to seek an alternative offense which usu. ends up being IADs, jumping (both which get shut down by F's strong anti-airs) or falling back to zoning if the option is available. F-ciel can also take initiative instead, and dash into the attack range to tag any sudden movements while being able to score a down by coupling low flicker (or high vs tall crouching characters). The other mid-ranged tool would be the High Flicker. This attack is a mere 9f in start up and covers a range that rivals Nero's 4C. It's also air unblockable, +1 on guard, ex cancelable for added shenanigans and jump cancelable on hit making combo follow ups relatively easy when fishing for a hit on grounded opponents. With these tools, F is able to cover a range unknown to C style.
General Spacing w/ Air-to-air and anti-air
C (JB, JC, 2B, 4C, 4B)
I'll just get this out the way now: 4C is ass for an anti-air, regardless of moon style but is semi-effective when anticipating jumps. JB and JC (usu. j7 for both) appear to be extremely effective in air battles (I've consistently seen good results w/ this in matches). 2B IMO is a bit similar to 4C in that it's used to catch jump attempts (usu. "set up" with dash>2b or something). It also seems effective for nailing players descending from air techs. As for 4B...no one, Jp or US, is using this for AA even though it has fast start up with clash lol.
F (JB, JC, 5C, 4B, 4C)
I don't know why but...JB for air-to-air gets results. It's fast and the hitbox is goofy (I guess). Spacing is to be heavily considered and you have to be a bit more precise with where you strike with the attack. In other situations, JC seems to cover angles that JB can't and it stays out FOREVER. IMO both C and F moon seem about even in their air-to-air abilities. As for anti-airs, F-ciel dagawd. You pretty much have to think twice about how to approach if your character lacks a multi-hit jump in. Otherwise you just get blown up with whatever followup may come after that backhand to the face. I honestly don't think many characters, let alone C-ciel, can even fuck with the practicality of this move. In addition to being an anti-air, 5C can blowup activations, multi-hit attacks, dps and do your laundry all in one.
General spacing Inside Game (Rebeats vs +Frames)
C
This segment is actually hard for me to comment on being as I don't truly understand the theory behind crescent's rebeat strings and inside pressure. For the most part, [ 2B, 3B, 5C, 5C>5C, rebeat 5a/2a hit/whiff ] seem to be the primary tools for holding forward momentum and feinting openings in C-ciel's attack strings. At the cost of max damage, C-ciel seems to be able hold players on defense a bit longer than F-ciel may be capable of.
F
This form is no slouch in that department, however. F-ciel is is capable of incorporating "fake" rebeat strings by use of whiffed A attacks and whoring plus frames on a few other normals. F is also has extremely late cancel points on her normals, allowing her to stagger at various degrees and letting her pace an attack string in accordance to the defender's level of "respect". Switching from slow, ascending strings to exploiting +f normals to advance forward or continue a new string (or both!) is enough to keep the opponent second guessing. I'll admit though that it takes a bit longer to figure out a player by these methods than mashing out rebeat strings until landing a hit. However, the upside to landing a random hits as F-ciel more often than not brings about a bigger payout with full dmg in return.
C (4B, BE4B)
...fucking useless. Anyone with experience in the match will be able to guard this every single time on reaction.
F (4B, BE4B)
...bullshit. Extremely strong meta-game going on 4B in attack strings. Semi-charged to flicker low for players who guard high on reaction to leg lift and BE4B to 214A for those who are just too damn slow to react. F-ciel really brings out this move's full potential and is definitely one of her stronger options.
General spacing 7th Heaven vs NO 7th Heaven
C
What can I say...7th is like the most versatile EX move in the damn game. Who can fuck with a FULL SCREEN, FULLY INVINCIBLE (after flash), FORCED DOWN attack at only the cost of 100% circuit. Sure this move is can easily be baited as a wakeup but that doesn't stop people from using this as a reversal in strings - strings which MOST characters have to respect or use other mediocre reversal options - or against full screen or ranged attacks or activations on reaction. Honestly, not many characters in MB have shit on 7th even with the many nerfs added to it.
F
That being said - stayfree, F-ciel? No, not really. The F form isn't exactly confined to a wheelchair with terminal cancer. F-ciel can still be and is (IMO) a very playable, competent and rewarding character to use in even the highest levels of competition. It's just that some of the players picking up or using F-ciel need to keep in mind that F-ciel =/= C-ciel in far too many areas. Instead of trying to use the character as "that Ciel without the Hiero", players need to go in understanding that these styles are not two different sides to the same coin but instead two completely different coins altogether.
On a personal note:
If ranking were to be considered, I'd say that C-ciel is only slightly better than F-ciel due to 7th Heaven and the 214B>214A knife set and THAT'S IT. I don't believe C is better by a large margin and in fact, I believe F to have some better matchups than C due to variety in neutral game and overall spacing. Because of this, I strayed from C-ciel as I don't like throwing myself at an opponent and I guess terribly when it comes to extensive zoning. F-ciel complements my playstyle as a whole and allows me to transition through many play styles in a match when necessary.