Well, there's cash on offer now!
This guide ranks highly on Google:
http://www.blurbdesigns.com/ZenUpgrade/index1.htm
Using this search:
http://www.google.co.uk/search?hs=1i...G=Search&meta=
The reasons are likely to be that it has been published for a long time - the more times a result is clicked on in Google, the higher up it goes. It is 9 pages long which helps, as well.