When I see that many spin articles, rewrite them 100 times and so on I wonder if it matters at all how well the article ranks in the serps? I am concerned about doing seo on my articles, checking on them from time to time to see if they are ranking well. Am I wasting my time. I would not think so as the more times my article is seen the greater the likelihood I will get a click through- traffic and possiblly the greater the likelihood another webmaster will read my article and post the article on his site- again traffic. Is this preferable to having 100 semi clones of the article that rank poorly or not at, as long as they have that backlink? ie does quality trump quantity or the other way around?
Quality will always trump quantity. In this case, you want to write unique articles that are optimized for the key phrases you want them to show up for. but they need to be high quality so that people will be able to read them easily, they will make sense, and syndicate the content. Instead of spending your time 'spinning' article so that you have 100 different copies of the same article, you should spend your time writing completely new, unique, interesting, useful articles.
In my opinion how well an article ranks in the serps is the true indicator of what Google feels about the article not PR. If an article ranks in the serps for your keywords it must be more trusted by Google (at least for those keywords), therefore outbound links from that page with the same keywords are likely more trusted.
I think that most people who spin articles are only out for the quantity of backlinks, they don't really care about those articles being portals that siphon people to their website.
quality is good but quantity also matters. if your competitor has 15000 somewhat OK links along with lot of junk ones, then it will still be hard to beat them with a handfull of quality links. i would say always try to get as many quality links as you can and if thats not enough, then start using the traditional link building methods