Blog posting and article submission is very popular seo technique to get good and quality back links. Improve your site page ranking in search engine. Its also very helpful to generate traffic on your website.
For me too both are good link building methods. Blog commenting & Article submission is an easiest way to get back links & traffic to a site. But, you have to do in quality sites to get a quality back link.
I think both are good. In both methods you need to pay attention content. It should be fresh and unique. In blog posting you need to update the content regularly and in article submission you should always pay attention on giving the very unique content for the site.
Both are very much important to promote a web site. Both are very effective parts of off-page seo. Both are important for getting quality back link, generate web traffics, increase web visitors and also page rank.