The above article is a nice find!!
I prefer using ipb as a paid forum.
I have worked as admin on few ipb forums, but don't actually use one.
I use phpbb, no money for ipb.

But IPB is a very good forums, with amazing mods to support it.
They have a good support panel and easy to manage control panel.
You get all the options ever needed in the default installation itself so, modding is less.
Most people always prefer ipb to vb.