Writing a good quality article, and giving it to article directories really does matter quite significantly. It really can give you hundreds of backlinks, some of them might even be of quite high value, but the most important is that you get a good long term effect from it. So, i suggest you do it with some quality articles!
Good post! Mass submission of low quality articles is next to useless. The real value is in getting quality articles distributed around the web.
GoArticles is decent. You don't need a professional writer, infact, they might do more harm than good if in question is say webhosting cons and pros of different types of article, which requires deep insight into a technical field. Professional writers don't tend to have deep insight into things outside of their field. Therefore, it's like shooting yourself in the leg.
A good quality article and submission of articles in good directories will always help you getting backlinks which helps increasing the traffice. I would suggest to submit the article in ezine articles.