I have been trying out some different article directories lately. I just signed up to Idea Marketers, and posted an article about comedy.
It's good for several reasons. Firstly it has high PR. It's been around for ages and has oodles of content and is thoroughly and regularly indexed by the search engines. (It's a lot like Ezine Articles in this regard.) However it is different to that directory in that your articles go live immediately, like at Go Articles.
There's obviously a huge number of people constantly scouring the site because even though my article hasn't yet been indexed by Google (I only posted it a few hours ago) it has already garnered at least 30 views. And it's not even in a very popular niche.
Also, as well as your author bio-box links, you get one right at the top of each article. I have read that this results in a very high click through rate. I haven't yet got any clicks since my article is so new, but I wouldn't doubt this is the case.
The only negative that I can see is that it doesn't have a rich text editor. While you can use the basic html tags to italicize words, etc, it just doesn't let you do it automatically.
And the stats are pretty basic. They just show how many view you're getting and don't actually list referring search terms and other information like Ezine Articles and Articles Base do.
But all in all Idea Marketers is clearly one of biggest and best article directories out there. I'll definitely be submitting more articles to it in the future.