I am happy that some of the most respected people in tech community decided to build a new age forum software. I am a regular on many over the ground and some under the ground forums. There is not doubt that a lot of the features on those forums are actually evolved to engage the users yet, they have become a bit stagnant in utilizing the more advanced features of modern browsers.
Discourse is a decent software and I am already running at least 2 forums on it. It is being developed at a very rapid pace and every week I few new features. Do try it out at http://meta.discourse.org