Yeah but EX Flash Kick will kill it 
I’d still abuse the hell out of Dan Knee on his wake-up since there’s pretty much fuck all he can do about it besides an EX Flask Kick reversal (can it beat that? x_x?)
One problem with aerial Dankus: Guile’s Air Throw beats LK Danku clean, and he can pretty much do it on reaction if you’re aiming to beat the Flash Kick.
Dan’s j.lk beats even EX Flash Kick unless Guile does it really late. Beats Ken’s hp Shoryu as well. LK Dan Knee on wakeup beats EX Flash Kick clean. Dunno about ultra.
In my experience, Dan Knee has beaten Guile’s air throw fairly consistently as long as you do it late.
Damn. My Danku must be broken.
Or maybe its my timing…
At that point, he’s already air thrown you. D:
I should’ve clarified, he can air throw you clean if he goes for it in reaction to your jump. You’d have to catch him from a very high angle not to get thrown.
The midair Knee of Justice will beat the EX Flash Kick, or trade with it if he does it late. Heck, just last night I had the midair Knee beat Guile’s Ultra and Sagat’s Ultra. Never underestimate the power of the Knee. 
As for the ground Knees, the EX Flash Kick will beat those, but if you time the Knee right you can bunnyhop over it, which gives you an opportunity to dash after him and punish.
When Guile starts to do the Sonic Boom > Air Throw trap, I have a few counters.
1: FA the Boom and release it as he comes down from his (likely whiffed) air throw attempt. This is best if you’ve been reliably jumping over the Booms beforehand, so that he reflexively tries for the throw even when you don’t jump.
2: Spacing spacing spacing. Do an empty jump over the Boom from far enough away that he can’t air throw you. Once you land, assuming he jumped forward, do a Koryuken to anti-air him.
3: The sneakiest one. Jump over the Boom, then do a midair EX Danku at the point where you’d normally do the Knee of Justice. He’ll jump after you and whiff his air throw because you stopped moving forward, and then he’ll eat your Danku.
Wow, maybe I should be going for Air Knees more than ground ones hehe. I think both Guile and Sagat’s Ultra eats ground Knees 
don’t go for air knees more than ground knees, if you mess up it’s crazy unsafe.
do try to work it into your game though.
well they can be used to bait out ultras from characters that like to ultra jumpins. The dk will generally float you safely over it. Seth, sagat, dictator to name a few. The nice thing is you can pretty much wait for them to ultra then mash the danku during their startup animation.
The only time the KOJ has beaten guiles air throw for me is if he jumps late and I hit him from above. ive wasted matches testing the KOJ on guiles air throws, and for me it never ever beats it. Like an above poster said if you do it too late, hes already thrown you, infact thats the prime situation for him to throw, i tend to think said guiles must be messing up and not throwing properly. Once I figure out im playing a guile where the air throw trap is his primary game plan i stay grounded or stick to neutral jumps.
The air knee certainly has its uses. It floats over Ultras, has high priority to beat or trade with many anti-airs (it eats Flash Kicks, Spinning Lariats and Headstomps for breakfast, and sometimes trades with Tiger Uppercuts, along with the aforementioned Ultras), and because it messes up your trajectory, it can be strong against certain normal anti-airs too. It’s a great tool for getting in on a zoning Dhalsim, for example, as it messes up the timing on his b.HK Yoga Knee counter, and will trade with or beat most of his air to air moves. Once you condition him to expect the Knee, then you can start jumping normally instead to catch him off-guard.
The downside to the Knee is the extra recovery time once you land, which is a pain. As long as you hit the opponent, though, that recovery doesn’t matter. Usually, even if they block the move, you’ll still be fine (you can even back-dash from Zangief’s SPD, as long as you aren’t at the top of his head when he blocks). It’s when the move whiffs entirely that you’re in real trouble, though fortunately, most of the methods people use to make the move whiff also leaves them vulnerable (like trying to sweep you when you land, only to find you’re airborne longer than they thought).
Since nothing is being compiled I figure I’d start a “hot potato” list. Cut and past, and, amend, annotate, expand, expound, delete, etc.
Once we have consensus that it is near enough to Saikyo perfection we can update the first post or make a new thread…
Sorry that my contribution is so lackluster…
General Strategies
Match-ups
Abel
Akuma:
dash in Koryuken or hk Danku to defeat air fireballs
watch for standing hk trap
watch for “Raging Demon” traps
if both are standing and Akuma goes for a Raging demon it is safe to simply jump back and punish him with jhk - smp - hk Danku
Balrog (Boxer):
cmk on wakeup - beats or is safe from headbutt
hk Danku beats ??? charge punches from full screen (can someone confirm which)
on blocked Danku expect a flurry of low jabs or headbutt unless you are VERY deep
Blanka
cmk on wakeup - beats electricity
jp Koryuken horizontal ball and sliding punch
punish rainbow ball with Ultra or hkDanku
Both horizontal and rainbow ball can be punished with Ultra or Danku if Blanka is near enough to the corner, depends on distance.
C. Viper
Cammy
hk Danku blocked Cannon Spike
watch for air throws
she is safe on a blocked Spiral Arrow if ONLY THE LAST HIT of her HK attack connects or from close distance with the single hit versions, expect an immediate Cannon Spike or throw attempt. You’ll have to feel out the opponent on this one.
On blocked multi-hit Spiral Arrow c.MK xx Gadouken or EX Dankuu can punish, s.MP is a MAYBE
Chun Li
watch for neutral jump split kick
Dan:
Taunt.
Taunt!
TAUNT!
Dhalsim:
Koryuken his long distance noodle arm shenanigans
air Danku can be used to hop over his backwards jump down punch trap
E. Honda
El Fuerte:
Danku, Danku, Danku
Fei Long
Gen
Gouken
Guile:
watch for air throw
air Danku has good priority to Flashkick
Can someone confirm that Koryuken or hk Danku is safe after blocking the first hit on his chk?
Ultra on blocked first hit of chk
Ken:
Ultra on landing will beat the fire-ball sweep trap
FA will beat jump kick sweep traps
watch for Hurricane Kick - DP and DP-DP-DP traps
M. Bison (Dictator):
dash out from head stomps
air Danku head stomps
hk Danku any slide kicks that come up short
Rose
Rufus:
Ryu:
see Ken
STAY ON THE GROUND WHEN HIS ULTRA IS CHARGED, he has too many easy combos to get you in the air and punish with an Ultra or, if you are very unlucky, a Super to an Ultra
Sagat:
distance and timing will allow air lk Danku to beat his Tiger Shot hk trap
air Danku can hop Ultra
Sakura:
Sakura abuse the hell out of Knee on wake-up. There’s nothing she can do about it other than EX Shou which will probably just knock you away and make her run right past you.
Seth:
see Dhalsim
Vega (Claw):
Zangief:
hit and run tactics
Can someone confirm that a hk Danku is safe when they try to close distance with a full screen Green Hand?
air lk Danku his lariats
Cammy’s “dragon punch kick” is called a Cannon Spike, the “cork screw kick” is the Spiral Arrow. If she uses the “right” version of Spiral Arrow so it hits with the end of the animation then she’s safe on block and probably expect a Cannon Spike afterwards. Otherwise a simple c.MK xx Gadouken or EX Dankuu can punish, doubt a c.HP can due to how slow it is but a s.HP might be able to (if close enough).
Sakura abuse the hell out of Knee on wake-up. There’s nothing she can do about it other than EX Shou which will probably just knock you away and make her run right past you.
Sugami, thanks. Added to my post.
You say “only last hit” but both Light and Medium versions of Spiral Arrow are only a single hit but both unsafe if done at point blank
You’d hope the better Cammy players wouldn’t spam the shit out of Spiral Arrow ~> Cannon Spike all the time but damn sure the not so good ones or “Spammys” as I like to call them will
You cannot HK danku a blocked horizontal blanka ball and I am 99percent sure you cant ultra it either on block if you did, they werent blocking, i swear, if you could hk danku punish a horizontal ball this would improve the match up for dan big time, maybe an ex danku can, not sure. The rainbow roll (the arching one) you can punish with ultra and hk danku, but they rarely use it because of how easily punishable it is.
Changed again… how does that look 
I Ultra it on block all the time but don’t know if its due to laziness on the part of the Blanka player… can someone confirm?
when I first started playing sf4 I used to counter pick blankas with cammy because she could easily punish blanka balls and all blankas did then was abuse horizontal blanka balls because most characters cant punish them.
In the corner, you can definitely punish Blanka Ball with ultra.