It's Microsoft's own fault
I'm sorry, but any stereotype that Microsoft or Windows has is Microsoft's own fault.
Microsoft botched Vista...the launch and the initial release. Even if they have turned things around with Vista SP1, they still have a ways to go to get over the overall image of Vista.
Apple, like any good company who is in direct competition with Microsoft, took advantage to exploit this weakness.
Apple did not make this stuff up for their ads. It's all true....simplified....but true, and that's what makes it a very effective advertising campaign.
You might not like it, or agree with it all the time, but it's working for Apple and their sales.
People don't want complex, I shouldn't have to THINK about a commercial, or have to go online to have someone explain it to me. If Apple can get across a simple point, such as Microsoft Office runs on a Mac (which we've seen in some of the VS ads), and if that point can get a potential buyer to think twice about an upcoming computer purchase, then they have done their job.
Plain and simple, Vista had problems (some might argue it still does), Apple took the opportunity to let people know that there IS another choice other than Windows.
Personally, I think the Apple ads work. No, they aren't the best, but they work. Some people on these forums seem to think that an ad needs to win an Oscar. An ad needs to sell a product. THAT is what the Mac VS PC ads do.
-Kevin