I disagree. vB4 had a lot features I needed at the time such as a CMS, a blog and a widget framework. Now it has way more, the most important new feature being a navigation manager. Xenforo 1.0 was barebones and lacked a lot of basic features that vBulletin already had. It couldn't even handle over 20 themes on shared hosting cause of some weird memory leak. Everytime you added an addon, language pack or theme it caused the whole site to be inaccessible to your users. VB 4.1 was superior in many ways, just not in speed and SEO.