Surge in comparative advertising

AdvertisingAge on increasingly aggressive comparative ads, perhaps partaking of the flavor of the political season. I wonder about those Microsoft "I'm a PC" ads, especially the one (or ones?) that begin with a guy who looks a lot like Apple's John Hodgman. But then I see Apple's vicious counterattack ad and it's clear that Apple has chosen to compete in the market instead of making a bad initial interest confusion claim.