If that was my site I wouldn't run any plugin, you can get the pretty url's with the stock vbulletin 4. What's to say DB's site will be up in a few years. I don't think anyone thought vbseo would vanish like it did.
You can "SEO" your site yourself and save your money.
The one good thing about DB's is they do have a converter so you can keep the same URL structure that your vbseo install had.