Talk:List of runes/@comment-192.223.163.6-20120328205832/@comment-77.249.233.124-20120330175310

^ nvm, I made some calculative mistakes there. Mpen is effectively only applies once while AP is applied on every hit.

Cutting through 650 effective HP (500 HP with 30 mres) will go slightly faster with AP quints than with mres quints. The ~5AP of a quint adds 3 dmg to a 100 base dmg spell for instance, 650/103=6.31 The ~2mpen of a quint on te other hand reduces their effective HP by 10, so we get 640/100=6.4 Overall not much of a difference since you still need to attack 7 times to actually kill someone with both runes, but the AP ones are clearly stronger by 0.1 attacks. And as effective HP goes up this difference only grows larger in the favor of AP over mpen. The only point I found mpen better than AP is at values of ~250 effective hp, but even the weakest of champs have at least double that in effective hp.

So yeah, take flat AP quints, not because they give you a huge advantage, but they give you the most and the best advantage in terms of early dmg. Though of course there are also things like movespeed quints to take into account besides dmg.