I have found bbPress to be the easiest to work with since it integrates nicely with the WordPress user sessions, you can also get a very extensive plugin to manage permissions which has native support for bbPress.
You’re posting here, so you’re experiencing Vanilla. It’s not awful but I’m not a huge fan either. I mega wish I was on bbPress which does a bit less but would allow this site to be 100% WordPress powered.
Changing forum software is no trivial task. Especially for someone like me who isn’t a very good developer (w stuff like databases). And also there is no Vanilla -> bbPress converter yet. I’ve talked to bbPress devs though and it seems likely someday.