Talk:Kog'Maw/@comment-2.83.26.101-20120526215115/@comment-3308937-20120527104809

Katarina used to be the focus of this question as well, except back then you couldn't hybridize her because her ult was either AD or AP scaling, not both. She had an AD scaling move, unlike Kog, but AP was still the preferred way of building her.

The reason for this is that while the ratio number may be higher AP is cheaper than AD (not twice as cheap though, AP is valued at 20g per point while AD is 36.66g per point). So, with Katarina and Kog, AD, per gold point, gives you more damage if you build pure AD rather than AP, at least you would if it wasn't for the kind of items that come with these stats. AD pales in comparison to AP, item-wise, when it comes to AD casters for a number of reasons.

First off: AD has no answer to Rabadon's Deathcap, the item which increases your Ability Power by 30% which makes every point of AP worth 15.38 gold (less than half as much as AD). The closest thing to a "big" item for ADs is The Bloodthirster, an item which makes you waste gold on lifesteal, a stat you can't take all that much advantage of, and is reliant on a stacking mechanism

Second off: AD has no magic penetration, with Kat and Kog the abilities they would be building AD for does magic damage, there is no AD version of Void Staff.

Third off: Usefulness and survivability. AP items generally just have more utility and can offer more survivability than AD items, see: Rylai's Crystal Scepter for slows on your skills and a large chunk of health, Will of the Ancients for a team-wide spell vamp and ability power boost, Abyssal Scepter for a magic reduction aura and magic resistance for yourself, Zhonya's Hourglass which gives you a stasis on its active, Athene's Unholy Grail (for Kog, not Kat) which gives mana regen, magic res, mana restoration on kill or assist, and cooldown reduction which lets you pump out more abilities, Morello's Evil Tome which gives mana regen, a healing reduction active, and cooldown reduction, and Deathfire Grasp which gives a large nuke in its active and cdr.