I still have an active license of a Vb and I have to say that it's really chaotic in licensed customer forum right now at Vb. There is no way that I am going to renew my vb license in current status. I am not paying a dime to those backstabbing bastards at Vb.
And so-called manager has vanished ever since the new pricing has been announced and left few support staffs to deal with the mess. What a day.
FYI, I had two active Vb licenses. I moved one of my Vb license to IPB in May 2008 and still retain one active Vb license.
There are huge differences in Vb3 and IPB3. But, to be bluntly honest, I never rely on mods because they are always unreliable. But if you do use lots of mods, I will say that Vb will be better for you.
Though some of really important and much-needed Vb mod features are built right in IPB as official features.
Oh, and IPB has an official CMS, Gallery, Downloads, and Blog (Which I am not so fond of.) as add-on.