^It's not outdated VB6 came out last month it's just annoying to put it simply they are both based on the same PHP language which is open source and also uses the same MySQL database, the only difference is UI and Vbulletin can still run on PHP 5.7 (this means "please come hack me bro") whereas xen requires 7. Vbulletin does have more features and addons (as well as users/site traffic to this day) xenforo has fewer bugs and is generally way more stable, and easier to install and update also more SEO and mobile friendly. I follow CVE's vbulletin last had one this year for a remote command execution, so they are obviously patching the thing.
It's a wise decision to switch if I was in the founder's position I would've done the same. I only have an issue with .me i guess .com was too expensive or not available. Nah out of all the choices why .me still is beyond me.