We recommend that you disable the vB archives, as inherently it will produce duplicate content, even if it was rewritten.
The archive actually no longer serves its original purpose, as search engines no longer need (and in some cases, penalise) a dedicated archive with only the essential links in order to crawl a site.
When the archive was first included in vBulletin, a trick used to improve SEO was to create a "link trap" for search engine bots, by linking to the Archive and making sure there were no links leading OUT of the archive. This meant the bots would crawl the same links over and over again, pushing them higher in the rankings.
vBSEO was a product with such a feature, if you've ever seen forums that had a bunch of links in their footers that looked like a row of numbers, and the links led to the archive, that was it.
The algorithms were changed years ago to actively penalise sites for doing this. With the sitemap feature in DBSEO, as well as recent changes & improvements in search engine bot algorithms, bots should be instructed to crawl the actual content, because that's what you want your users to see.
From a purely user point of view: If you search for something in Google, find a thread, then discover it's the Archive, you're forced to click the "view full thread" link in order to see quotes correctly (quotes are horribly confusing looking in the archive), as well as rich media like images and video.
While you personally may be fine with doing this, studies have shown that the average user has a very short attention span when it comes to finding the information they need. If a page takes too long to load, or they have to click links in order to actually view the information they're looking for, they are very likely to simply leave the site rather than go through that extra effort.
That is, unless that result is literally the only relevant result for their search, which in most cases is unlikely.
