Interesting thread! I have been bouncing around looking for an interesting/fast/good option for my site at ne1up.com (between hosting right now) and liking what I see here. Discourse has been my other top option, followed by Vanilla.
Unfortunately the install is above my paygrade so I had thought about trying out the $20/mo package at DiscourseHosting, something I hate doing, but they're nice. So I was pleasantly surprised to stumble upon NodeBB earlier. This seems faster, bit cleaner and less cumbersome to me in several ways.
I am curious, the reason I am leaning towards Vanilla right now - I have a home page (WordPress) where I post and I would like a corresponding post/thread to be created on my forum when I do that - and I would like the comments from the blog post go to the thread, and vice versa if possible.
Vanilla offers most of this functionality if not all - I am really unsure about Discourse - but what about NodeBB?
I don't mean to hijack, it's just something that for some of us might be useful, that WordPress integration and cross-posting.