I am considering to move to XenForo since I heard a lot of people say it's a very good forum software and something that got my attention is that it's developed by ex-employees of Jelsoft co. I've been a vbulletin customer since vB3.6.x, and now I have the latest vB version. Back then before they released vB4 i feel like the script and devs was way better (imo) ..
Some things I would like to hear from other customers is the resources usage compared to vbulletin.
I have a forum with over 1.1 million posts and 50k users and it's running fine with vB so far.
One of the main reasons I've never moved out of vB it's because of the huge amount of plugins that it has (at vbulletin.org), I'd love to know if XenForo has a similar addon/plugin system and if there are coders providing free/paid mods.
And lastly, I like how the vbulletin themes look, I currently using themes from completevb.com. Is there any website that offers templates similar to completevb ?