I originally chose Agora, it looked ok, and seemed to offer what I wanted, but I tried to update two days ago, and no matter what I did, it just refused to install. Finally I was left frustrated with a broken site.
After spending two days dismantling the site, reconfiguring, clutching at straws and otherwise wasting time trying to make it install, I bit the bullet, deleted everything and installed fresh Kunena 1.5.4.
Wow! Impressed? Oh yes! It installed perfectly first time, configuration is easy. Refreshingly polite forum support is excellent, oh yes, and so is the on-line documentation/Wiki!
Considering the relative short time in development, this is an amazing implementation. There is no other choice, Kunena is the flagship for sites that need a Joomla 1.5 native forum/board.
I wish I had installed kunena first time round!
Well done and thanks for a great product!