Page rank is not so important and according to Google never was. They have said they look at 200+ parameters when ranking sites but of course no details. Most of what has ever been written or said about this stuff is speculative by nature.
Google Ads = high ranking is obviously not correct. Many that go from no ads to ads will probably see better seo results. Not because of the ads, might steer some people away!, but because they optimize a not-optimized site. That often follows implementation of ads, increased awareness of keywords for example.
May be check Matt Cutts blog http://www.mattcutts.com/blog/
he is head of SEO thingys at Google. If he clear his throat 1000s ears are wiggling
A site can get ripped off any ranking if TOS is pissed on, including adsense so may be that dude should complain to Google.
I recently saw a video of "SEO in 2010" by seomoz (I think). He said Google is aware of dirty tricks (related to paid ads, buying domain with high ranking and use them, from what I remember) and are starting to clean up, will increase effort the next 1-2 years - what he said. That not every data/result is valid is of course true. Complain! They have forums for this and his site is "important" enough to get some notice, eh clicks
This is my idea of SEO importance http://powazek.com/posts/2090
- tabloids the web but still interesting to follow both white and black hats.