I am using Simple:Press with 2.51 and find it very easy to use - just plug it in, configure it from the admin panel to give chosen titles to the new forum boards you want, and it just works straight away.
If you check out the forum pages on that yellow swordfish site, one of the forums is a "strut your stuff" board - there you can find links to a bunch of sites all using Simple:Press. Have a browse around those sites and see if it is the look and feel you would like.
The upsides of it:
It works at once.
The front of it integrates at once - its embedded in a new "Page" of your blogsite
The back of it integrates at once - it shares users with wordpress - no need for seperate login
The support is good - the developer listens to users and adds more features all the time.
It has the same/similar editors as wordpress - users can (depending on admin settings) link, add pictures, upload pictures etc using the same sort of wysiwyg editor like wordpress.
It has the ability to really link between the blog and forum - i.e. new blog posts can automatically spawn forum threads for discussing them - you don't have to use this if you don't want to, but it is there.
I have not used WP-Forum - hopefully you'll get some feedback from others on what that is like - the forum at the link you put does not have a lot of recent activity, but maybe that's because the plugin has no current bugs.