I tried to use VaultWiki, but it was too limited in regards to wiki functionality. Yes you could have wiki pages, but you couldn't do per-namespace/area navigations which made it awkward to navigate with more than one namespace/area. There were also constant bugs that would break functionality or make it problematic to use.
I've been playing around with Tiki Wiki (as stated previously) which takes a lot of setting up and configuring and the like, but the flexibility and functionality far out weighs what is offered by VaultWiki. I'm probably going to look at getting a bridge made that uses XF2 credentials, it's just a matter of priorities at the moment.