If IPB3 weren't such a mess from the administration and configuration point of view, I would swith to it (ihave licenses for both). While I can understand Timan's point of view regarding the ease of theming, simply running and admining a site, vB has done their homework, with end users in mind, far better than IPB has. On the other hand, IPB just released an iPhone app to connect to IPB sites, which is VERY well done, and they appear to understand that their users and customers come from several platforms - the vB designers and managers have admitted to 'tolerating' Mac users, and most likely will never support Safari with their text editor (while many others do). So, yeah, short of writing your own forum, difficult to decide.