I have installed IPB on a test site. At one time I had all my sites on IPB. I left vBulletin during the version 4 debacle and imported the sites to IPB.
After a few years I decided to switch to xenforo. I haven't looked at IPB in a few years. I got an email about IPB 5 demo and looked at it.
I went into the client area and renewed one of my old licenses.
Site can be found at:
http://forumadmins.org
I will open it to guest posting once I figure out the permission system again. It's been a while.