This isn't fair. IPB and VBulletin is paid software, whereas PHPbb, MyBB, and SMF are self funded projects.
Why isnt it fair? Just because they are paywayre and some are not dosen't mean you can say one is better than the other. For example Photoshop is far superior to GIMP or Paint.net but GIMP is probably the closest freeware alternative to Photoshop (as far as i know anyway). Thats just how it is.