Which are the top quality article sites?

They're sites in your niche, that already have targeted traffic.

A top quality article site for "registry cleaner traffic" is a useless site for "skin-care traffic", and vice-versa. It's all about relevance.

To imagine that a site like Squidoo, HubPages or InfoBarrel can somehow, magically, be a "top quality" site for both of those and for 98 other niches, too, is - to put it very politely - "less than optimal reasoning".

The top quality article sites, from your perspective, are the sites you own and control yourself.

Your own site is, and should always be, the top one.

After that, the next most important are sites that already have the targeted traffic you want to attract to your site - all the relevant niche sites.

There's "the hard way" and "the easy way", with article marketing.

The difference between the two is typically the difference between making a living (and building a real, asset-based business), and not making a living (and building nothing).

The hard way - and it's very, very difficult indeed - is to try to draw targeted traffic to your articles.

The easier and overwhelmingly more profitable way is to put your articles where the targeted traffic already is, and use the articles to draw the traffic from there to your own site.

These three threads may help you ...
Best way to submit articles?
What is the Best site for Posting Articles
Best sites to submit articles?

Nobody making their living from article marketing wants to try to generate traffic to articles on other people's sites, rather than on their own: those articles are there to attract the traffic which is already there because of the subject-matter of those sites.

For all the reasons explained in this post, the last thing I'd ever want is for a potential customer to type into Google a keyword from one of my articles and find the article on someone else's site. The copies on others' sites are there only because those "others" already have regularly visiting, targeted traffic I want to become my visitors, subscribers and customers.

It's exactly as you summed it up, yourself: what you need is ... Or, more specifically, sites whose existing traffic has value to you on its own.

Key concept: regarding places like Squidoo and HubPages, it's all too easy easy to imagine that you're generating traffic from other people's sites, when all you're really doing is sending to those other people's sites traffic which you could instead send to your own (and getting only some of it back ).

There is no top site. Guest posting (on highly relevant/related blogs), with a strong call-to-action at the end of the post is the way to go.