Education costs money. Ignorance costs more.
As someone involved in both projects, at the moment, the wiki is winning for me. Why? I think because it feels more like we are writing collaboratively to build up something that will look pretty close to a finished resource that we can use in the future. The blog seems to be more of a collection of links and comments, which doesn't flow in the same way. However, I accept that tagging may pull something out of the bag when it comes to the end of the blogged project!
The wiki has the same tagging capabilities - if we are disciplined enough to use them! ;-)
I am certainly very interested to see how you get on because I am at the very early stages of experimenting with these particular tools. cheers Sarah