Meta keywords and description aren't even used by major search engines any longer as ranking factors. (major as in Google, yahoo and MSN)
What settings did you test that don't work?
Automatic thread tagging isn't an SEO mod. Just about any one will tell you that thread tag pages, are junk pages and should be blocked with a robots.txt file to keep your SERPS clean and relevant.
I'm not saying vBSEO is like the install and forget SEO mod either, if you do that of course you wont get the results. You still need to get link backs and build content. Their marketing is rather slick and semi-misleading i will agree with you there as well. I'm only saying if I had to choose, I'd either use vBSEO or no SEO modifications what so ever, other than manual template edits.
The settings I tried are the 404 redirect ones, which didn't work. Those are the most obvious ones.
I'm online with the guy who runs that forum and we're doing some other stuff to upgrade his forums, and then we'll try again.
As I said, I can duplicate its functionality with free stuff, and even do better. Why pay for their BS marketing?