I've recently watched sevaral pub games and notices that juggernaut almost always got mask of madness one of the first. I wonder why is that? Was there any kind of patch for him and this item is now so vital? I know that using mask during ultimate lets you make a several more usual attacks but isn't it better to get desolator which will improve damage output both from ult and regular attacks?
In the 6.81 and 6.81b patches, Juggernaut's base attack time was reduced multiple times from 1.6 to 1.4. This lowered BAT makes any attack speed-enhancing effect more effective. The berserk attack speed, combined with the buffs to Juggernaut's critical strike passive (in patch 6.83) make him a very powerful right-clicker even early in the game (MoM is only two 900-gold pieces, easy to farm). Further, the berserk effect's movespeed makes it easier to farm the jungle, escape, or chase without being kited (a problem for all melee heroes).
As a note:
6.80 level 7 Juggernaut with Mask of Madness active - 0.67 seconds per attack
6.83 level 7 Juggernaut with Mask of Madness active - 0.58 seconds per attack
And it scales better with more Agility and attack speed gear from there.
because it synchronizes very well with juggernauts whole skillset.
his ability to negate magic damage with his q and heal rapidly with his w both combat the increased damage from MoM active, as he is also one of the strongest early rightclickers the lifesteal is a very useful ability to guarantee early fights go in his favor, the movespeed is very very useful on him as with all rightclick heroes.
also, while in his ultimate, juggernaut will actually auto-attack the enemy he hits with omnislash, getting mask of madness allows you to increase the number of autoattacks you land while in your ultimate, effectively increasing your overall damage more than an aghanims sceptre.
he's the carry that basically benefits the best from PRM building (Phase boots, Ring of Aquilla, Mask of Madness)