*Copied segment from one of my posts in a diff thread*
If you were going specifically for mitigation through Knock Downs I would definitely suggest War Mace, even over Battle Axe which is SUPPOSED to be The Definitive KD Set. The thing about Battle Axe is that most of its attacks simply have a moderate to high chance of causing KD, that being the gimmick of the set. War Mace supposedly does better dps due to Clobber (which is a pretty amazing attack) but Battle Axe has slightly superior DPA on the majority of its attacks. Still War Mace has 2 powers with KD and one with KU but their chances are all higher than Battle Axe's similar powers. I heard all this from one of my friends when I was defending Battle Axe to him, and it turns out he was right and War Mace is better in certain respects, especially getting some GARUNTEED KD when you need it. If you are decently lucky, you can still find Battle Axe to cause good KD but the inverse is that if you are unlucky, you can find no KDs when you really need them.
Here are some numbers directly from the game comparing similar attacks. (scaled to lv50)
Battle Axe: Swoop
DPA: 51.96
Cast Time: 1.83s
Recharge Time: 12.00s
70% chance for KU
War Mace: Jawbreaker
DPA: 44.67
Cast Time: 1.83s
Recharge Time: 10.00s
75% chance for KU
Jawbreaker does actually do a bit less damage, and has a (barely) higher chance to KU and a faster recharge, all in all between these two I would admit Swoop is better. Axe wins this one.
Battle Axe: Cleave
DPA: 49.40
Cast Time: 2.33s
Recharge Time: 15.00s
80% chance for KD
Cone: 10ft 20degrees up to 10 targets
War Mace: Shatter
DPA: 40.81
Cast Time: 2.33s
Recharge Time: 12.00s
100% chance for KD
Cone: 8ft 45degrees up to 5 targets
So here's a similar situation. Again Cleave deals the better damage, but somehow Shatter gets the better KD and recharge again. The cones are different, but Cleave can hit more targets and is a little narrower, and Shatter gets the 100% KD and wider cone. I would call these two powers evenly matched, because of the situational importance of having a wider cone.
Battle Axe: Pendulum
DPA: 39.62
Cast Time: 2.00s
Recharge Time: 15.00s
50% chance for KD
Cone: 7ft 180degree up to 5 targets
War Mace: Crowd Control (my friend calls this "THE BEST MELEE ATTACK IN THE GAME!!!1!!1)
DPA: 33.57
Cast Time: 2.00s
Recharge Time: 12.00s
100% chance for KD
Cone: 8ft 180degree up to 10 targets
You may notice a pattern here, that again Pendulum has better DPA but Crowd Control gets the 100% KD and faster recharge. However this time it is the War Mace attack that gets the 10 target cap and poor Battle Axe only gets 5 targets. I find that this fact counters out the previous powers where Battle Axe got the higher target cap, becase hitting 10 people with that narrow cone is HARD, and hitting 10 people with Crowd Control is easy peasy. Also the discrepancy in the KD is huge here, with Pendulum only having a 50% chance and Crowd Control having 100%. Crowd Control is indeed a mighty attack, Mace wins this one.
Battle Axe: Whirling Axe
DPA: 15.62
Cast Time: 2.67s
Recharge Time: 14.00s
50% chance for KD
War Mace: Whirling Mace
DPA: 17.50
Cast Time: 2.67s
Recharge Time: 14.00s
30% chance for 2mag Stun for 5.96s
In this last case, Axe has an AoE which can KD while Mace's cannot KD. This is also the one situation where Mace's AoE does better damage than Axe's. I think that Mace has enough KD that it doesn't NEED the KD here, but the minor Stun effect will rarely help vs tough enemies. Mace wins this one.
In summary, if you want to keep any melee toon alive by keeping your foe off his feet, War Mace is the way to do it. Two Cones with 100% Knockdown and 12 second recharges, a high recharge build can use these two powers with proper timing to keep an enemy (or small group of enemies) floored constantly. If you don't have quite enough recharge to do his, adding Jawbreaker in with its 75% chance still means you can keep a single enemy floored most of the time with only moderate recharge. Battle Axe cannot say the same thing, since there is always the chance that your attack chain will have bad luck and not KD right when you really wish it would, although you will do slighty better damage on most attacks with Axe. Mace is also completely capable of mitigation through Stuns as well, which Axe doesn't do at all, furthering the argument that Mace is the ideal mitigation set. Finally, Clobber has ridiculous DPA, and although I don't necessarily agree that this one attack negates the fact that most of the other Mace attacks do less damage than the Axe ones, it is certainly worth noting that Clobber will keep Mace pretty freaking good when it comes to DPS. In the end you can stick with Axe if you want to though.
"Look, personally I just want a new issue to feature changes that don't cause a mass exodus of players..."
Issue 17: We Didn't Break Anything!
How to suck at CoX
Literally the Best Build Ever: Years in the Making
Buff Battle Ax!
Raise Pendulum's cap to 10 baddies! Swap the target cap with Cleave, like it should be!
Add bleeding ticks to the single target attacks! (See broadsword for the bleeding mechanism.)
Weapon redraw, lethal damage, and poor mitigation performance makes mauk a sad boy!
Buff Battle Ax! Ax-wielders are people too! 
/em protest
I was fiddling around with Mids and I realized that this could be an amazing combo: BA/Fire scrapper. The damage mitigation via KB plus the crazy amount of AOE damage, plus the strong single target damage, plus 3 force feedback procs in AOE attacks? I am so tempted to make one of these now. This could be ported to a brute as well, although all the KB might actually be too much mitigation as it would interfere with Fury. Also, this could be modified to fit a TW toon as well... man would that be nuts...
Anyway, just something to play around with
Hero Plan by Mids' Hero Designer 1.952
http://www.cohplanner.com/
Click this DataLink to open the build!
Level 50 Magic Scrapper
Primary Power Set: Battle Axe
Secondary Power Set: Fiery Aura
Power Pool: Speed
Power Pool: Leaping
Power Pool: Fighting
Power Pool: Leadership
Ancillary Pool: Blaze Mastery
Hero Profile:
Level 1: Chop -- KntkC'bat-Acc/Dmg(A), KntkC'bat-Dmg/EndRdx(9), KntkC'bat-Dmg/Rchg(13), KntkC'bat-Dmg/EndRdx/Rchg(15), C'ngImp-Acc/Dmg/EndRdx(17)
Level 1: Fire Shield -- RctvArm-ResDam/EndRdx(A), RctvArm-ResDam/Rchg(9), RctvArm-ResDam(40), RctvArm-EndRdx(40)
Level 2: Gash -- KntkC'bat-Acc/Dmg(A), KntkC'bat-Dmg/EndRdx(17), KntkC'bat-Dmg/Rchg(19), KntkC'bat-Dmg/EndRdx/Rchg(19), C'ngImp-Acc/Dmg/EndRdx(21)
Level 4: Blazing Aura -- Erad-Acc/Dmg/Rchg(A), Erad-Acc/Dmg/EndRdx/Rchg(46), Erad-Dmg(46)
Level 6: Healing Flames -- Numna-Heal/Rchg(A), Dct'dW-Heal/Rchg(25)
Level 8: Swoop -- KntkC'bat-Acc/Dmg(A), KntkC'bat-Dmg/EndRdx(21), KntkC'bat-Dmg/Rchg(23), KntkC'bat-Dmg/EndRdx/Rchg(23), C'ngImp-Acc/Dmg/EndRdx(25)
Level 10: Hasten -- RechRdx-I(A), RechRdx-I(11), RechRdx-I(11)
Level 12: Combat Jumping -- LkGmblr-Rchg+(A), LkGmblr-Def(13)
Level 14: Super Speed -- Zephyr-Travel(A), Zephyr-ResKB(15)
Level 16: Build Up -- Rec'dRet-ToHit(A), Rec'dRet-ToHit/Rchg(29)
Level 18: Whirling Axe -- Erad-Dmg/Rchg(A), Erad-Acc/Dmg/EndRdx/Rchg(27), Erad-Acc/Dmg/Rchg(29), Sciroc-Dmg/EndRdx(31), Sciroc-Acc/Dmg/EndRdx(33), FrcFbk-Rechg%(33)
Level 20: Plasma Shield -- RctvArm-ResDam/EndRdx(A), RctvArm-ResDam/Rchg(43), RctvArm-ResDam(45), RctvArm-EndRdx(46)
Level 22: Boxing -- Empty(A)
Level 24: Tough -- RctvArm-ResDam/EndRdx(A), RctvArm-ResDam/Rchg(42), RctvArm-ResDam(43), RctvArm-EndRdx(43)
Level 26: Cleave -- Erad-Dmg/Rchg(A), Erad-Acc/Dmg/EndRdx/Rchg(27), Erad-Acc/Dmg/Rchg(36), Sciroc-Dmg/EndRdx(36), Sciroc-Acc/Dmg/EndRdx(36), FrcFbk-Rechg%(37)
Level 28: Burn -- Oblit-Dmg(A), Oblit-Acc/Rchg(37), Oblit-Acc/Dmg/EndRdx/Rchg(37), Oblit-Dmg/Rchg(39), Oblit-Acc/Dmg/Rchg(40), Oblit-%Dam(42)
Level 30: Weave -- LkGmblr-Rchg+(A), LkGmblr-Def/EndRdx(31), LkGmblr-Def(31), Empty(42)
Level 32: Pendulum -- Erad-Dmg/Rchg(A), Erad-Acc/Dmg/Rchg(33), Erad-Acc/Dmg/EndRdx/Rchg(34), Sciroc-Acc/Dmg/EndRdx(34), Sciroc-Dmg/EndRdx(34), FrcFbk-Rechg%(39)
Level 35: Ring of Fire -- RechRdx-I(A)
Level 38: Fiery Embrace -- RechRdx-I(A), RechRdx-I(39)
Level 41: Fire Blast -- Empty(A)
Level 44: Fire Ball -- Ragnrk-Dmg/Rchg(A), Ragnrk-Acc/Dmg/Rchg(45), Ragnrk-Acc/Rchg(45), Ragnrk-Dmg/EndRdx(48), Ragnrk-Knock%(48)
Level 47: Maneuvers -- LkGmblr-Rchg+(A), LkGmblr-Def/EndRdx(48), HO:Enzym(50)
Level 49: Temperature Protection -- S'fstPrt-ResDam/Def+(A), S'fstPrt-ResKB(50), Aegis-Psi/Status(50)
Level 50: Cardiac Core Paragon
Level 0: Freedom Phalanx Reserve
Level 0: Task Force Commander
Level 0: Portal Jockey
Level 0: The Atlas Medallion
Level 50: Reactive Radial Flawless Interface
------------
Level 2: Swift -- Run-I(A)
Level 2: Health -- Numna-Regen/Rcvry+(A), Numna-Heal(3), Mrcl-Rcvry+(3), Mrcl-Heal(5), RgnTis-Regen+(5)
Level 2: Hurdle -- Jump-I(A)
Level 2: Stamina -- P'Shift-EndMod/Acc(A), P'Shift-EndMod(7), P'Shift-EndMod/Rchg(7)
Level 1: Brawl -- Empty(A)
Level 1: Critical Hit
Level 1: Sprint -- Empty(A)
Level 2: Rest -- Empty(A)
Level 4: Ninja Run