Apple’s latest Leopard operating system was released at a very good time when Vista was constantly getting delayed and getting lots of bad press in general. Apple was very smart in using this to their advantage, and the ads seem to be effective in getting people to switch. I like this Audi ad that directly targets the Lexus and their self parking assist which got a lot of attention when it was released: http://tinyurl.com/6dmg2d. So I think its fine to take a direct hit at your competition, just do it in a clever way that doesn’t come off as being too desperate.