Doing some rudimentary shot type analysis just to see if my suspicions are correct. Nothing about this is precise because I don't know how to hack this version of DMF.
Futo's base shot is 10% more powerful than Reimu's and Marisa's.
Hypers last for 1800 frames (30 seconds), with the timer pausing whenever there are no enemies on screen and any time the player cannot shoot (e.g. during dialogue). Obviously, 30 seconds will get a lot more done during stages than bosses.
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Testing on Yuyuko's first spell on Normal, the clear times (for focused damage) I got were:
ReimuA: 19.26
ReimuB: 18.12
ReimuC: 16.32 (focused), 19.26 (unfocused), <timeout> (homing shot only)
MarisA: 18.17
MarisaB: 17.15
MarisaC: 20.03
FutoA: 17.52
FutoB: 15:54 (all shots), 21.06 (Futo only), ~35.00 (Tojiko only; DMF crashed upon spell card capture)
FutoC: 14.17 (mostly unfocused), 20.04 (focused, medium distance)
On Yuyuko's third spell on Normal... (this is something of a test for "if all shots hit", ish)
ReimuA: 23.52
ReimuB: 19.45
ReimuC: 18.26
MarisA: 22.48 (not a typo)
MarisaB: 18.39
MarisaC: 19.41
FutoA: 21.46
FutoB: 20.05
FutoC: 23.19
On Normal Cirno, with hypers... (note that Cirno comes in from the top-center right, so shot types that can hit that from the center are at an advantage)
ReimuA: 5 shots fired (This is somewhat unfair, as this doesn't really measure the strength of her hyper options)
ReimuB: 1 shot fired
ReimuC: 3 shots fired (contrast 5 shots with no hyper)
MarisA: No shots fired (unfocused)
MarisaB: 3 shots fired (far), 1 shot fired (medium), no shots fired and a little less time than MarisA (close), 1 shot fired (unfocused, close) (contrast 5 shots with no hyper)
MarisaC: No shots fired, about the same length of time as MarisA
FutoA: Difficult to discern hyper power because of the nature of the shot.
FutoB: 3 shots fired
FutoC: 9 shots fired (far), 5 shots fired (close)
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ReimuA: Standard homing shots that have the power to chase backward when focused. Hyper adds a horizontal array of options to shoot straight ahead.
ReimuB: Standard persuasion needle, although its range seems to be on the narrower side of the official games. Hyper completes a triangle of options to shoot straight ahead.
ReimuC: When firing, includes a gohei that swings about midway up the screen from Reimu. Focus to add a slow-moving homing shot. Hyper adds two more gohei on either side of the existing one; in addition, point items that touch the gohei are auto-collected.
MarisA: Penetrating lasers that have a (relatively) wide dispersion unfocused and a very narrow focus. Hyper adds eight more lasers that roughly converge midway up the screen when unfocused, and angle out to cover most of the screen when focused (similar to Marisa+Alice in SA).
MarisaB: Missiles with splash damage after the fashion of Marisa+Nitori in SA. The options rotate as you move laterally with progressive velocity, though I don't know if this is practically meaningful. Hyper increases damage and increases the splash damage radius to cover something like half the screen in either direction. In addition, once your main shot hits something, if your options are close enough they will lock onto it until it dies, even if you move away.
MarisaC: Five short-wave shots similar to the B-type from UFO. Focus to slightly alter the shot pattern and fire them backward as well. Hyper removes all but your main shot and causes your options to enlarge and rotate around you (increasing rotation speed as you hold fire), dealing damage on their own. Focusing causes them to spread out slightly. While you can stop firing to keep your options in one position for the joy of poking a fairy with a big orange crystal, this is not optimal as you aren't doing damage from your main shot.
FutoA: Unfocused it's a spread shot; the spread is weak and seems to stop in place for reasons I'm not sure of. Focused, the options' shots have slight homing tendencies like PCB SakuyA. The hyper charges power up to three times as you keep shooting, and when you release the shot button, Futo will unleash a laser corona according to how much charge you had.
FutoB: In addition to a straight-ahead shot similar to ReimuB, when you press the shot key Tojiko will appear in front of you, fixed in position, and fire straight ahead until you release the shot key. On hyper Tojiko will independently move toward enemies and shoot them down.
FutoC: Futo has a wind aura around her that deals a ton of damage on its own. When focused, Futo shoots a large wind shot in the direction opposite your movement when you focused, and keeps her wind aura in each direction except where you were going when you focused. The hyper does the same, but includes another wind shot that homes in on enemies. The wind shots will decrease bullet velocity and potentially change their angle, though I don't understand the means by which this happens.
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Conclusions...
Unsurprisingly, ReimuA has low overall power, which makes the bosses miserable. However, her ability to potentially hit any target anywhere on the screen is probably attractive in Stages 3 and 5 in particular. She has one of the better hypers for stages, as she can cover most of the screen with moderate firepower.
ReimuB is solid as usual.
ReimuC (Goheimu) is hilarious and, without hypers and under optimal conditions, the best boss-killer in the game. Her major downside is that she struggles outside her optimal conditions (focused and medium-distance from the target, e.g. all those attacks that force you to dodge from midscreen). She makes up for her shortcomings with her auto-collection boost during her hypers, which is your best bet for maxing out your resources.
MarisA is, without hypers, more or less exactly as powerful as ReimuB and comes with narrower range. On the other hand, her hyper (and probably her hyper liberation as well) is substantially better, provided you're able to stay unfocused when you want. Also, obligatory additive blend complaint.
MarisaB is surprisingly strong for a gimmicky shot type. Her range during a hyper is surprisingly good, which combined with her damage output makes her a competent alternative to ReimuB.
MarisaC... I'm still going to need convincing on. She has a competent back-shot but her forward shots are too dispersed to deal much damage. Her hyper is very strong and has demonstrated potential to cheese some attacks, but it still seems like it will make a lot of the game more difficult than it has to be.
FutoA is... odd. I'm not a big fan of charging attacks, since releasing the shot key is one more thing I have to remember. Her hyper shot can clear the screen of enemies, but by that time they've already dumped bullets on screen. At least her focused shot is very competent.
FutoB is scary if she can get all her shots to hit. However, if you can't manage Tojiko or if you're fighting moving targets, this shot type becomes a liability. Her hyper fixes this problem in spades.
FutoC is, aside from the obvious best choice in a no-focus run, a very strong alternative to MarisaC in the point-blank category, with the ability to clear stages by ramming enemies. At a distance, though, she leaves a bit to be desired. Her ability to slow bullets down is amusing but I'm not sure how practical it is, given that it can turn fast-moving staggered bullets into a slow-moving wall.