I know very little about VBulletin, but what I DO know is that after running Classic for a couple years, switching to Threads was like stepping out of my work shoes and into a nice warm pair of slippers.
Very comfortable and easy to understand. I too find PHP more intuitive than I did Perl and have had a great time with it.
Along with Threads, comes the backing of Infopop who has great support, but you also get this site with all the excellent members, whose knowledge combined is amazing!
I'm a member of a couple VBulletin boards and I find the Threads user interface more comfortable as well. So I think I'd have a very hard time being convinced to switch at this point. In the end it's a personal choice. I chose Threads, but that was my choice.
