I've been using this product on several of my test sites for the past few weeks. I am amazed at how far along this extension is, and how little trouble I've had considering its only in Alpha release at the moment. Typically, with Alpha releases I have at least one issue getting the extension to work, but this one had no issues for me (with phpBB) out of the box. It worked exactly as it was claimed to have worked on their site.
I've also been very impressed with the speed at which this extension is developing, and the very fast responses from the developers and other team members on their website. If you've been waiting for an easy way to integrate your phpBB, SMF, and countless other forums with Joomla, this is the extension you need, hands down!