Personally I always spin my articles, although this being said if you release a press article that gets picked up by other sites (with your links) then they all count. The same goes with article directories, people can copy the content onto their sites as long as the links stay there. So it should not have any impact on the links but just don't use any duplicate content on your site.

Here is my thoughts. Most article directories will accept your article even though the same article is posted at other places, but those article directories usually have low PR. I have found that the high PR article directory sites and the ones that matter will only accept unique articles.

So if your goal is to build backlinks, then getting backlinks on high PR sites should be a goal too. So I would suggest to make one article to submit to the low PR article directory sites, then spin your article 10 times to have ten unique articles. Then find the top ten highest PR article directories and submit one of your 10 unique articles to them. Thats just my 2 cents.

Iffsute SEO wise, I spin my articles. But my website's content are entirely original and of high quality articles.

Quality is the key, generally those automatically article directories won't be too strict. But what you need to pay attention is Panda, we know it's still out there.

HI
if you post same spinned article on different sites then its seen as a duplicate content, so submit different article for every site.

It only takes about 3 minutes to edit a 300 word article. It's worth it.

Google doesn't like to re-index the same content over and over, so by making each article more unique you will increase your indexing rate.

The Article spinning is not a good help at hall. The recent updates about Google manifest that they would get rid of the spam soon. They are going to prefer perfect English method for their right selection. Besides, the article directories that I usually submit articles like Ezine and Sooperarticles etc have too taken steps to promote genuine work. Besides, the true backlinking is also ensured to make these article directories author friendly.

I have read Google blog about taking care of spam effectively.