Article Submission is it effective than directory submission?

Yes, it is MUCH MUCH more effective than directory submission. But let's be clear on what, exactly, we are comparing here.

These are two of the cheapest sources of link-acquisition. And Google knows this. Google is EXTREMELY good as discounting links that are easy to acquire. They understand that links are currency in this new online world and have factored all those things into their algo.

Why are article sites better than directories???

1) Keyword density of the page your link is on. You can make that page about your topic.
2) Fewer outbound links on the page where your link is.

Why Article Sites are still not THAT great:

1) Many are PR0 or PR NA.
2) Many only have authority for the home page.
3) Your content sinks rather fast into their site.
4) The domain as a whole has MANY outbound links (bad ratio).
5) The site is generic and not about your topic (even if your specific page is.

For these reasons, a link from a site that is entirely about your topic will be MUCH MUCH more strong than a article site link.