Importance: Low

Type: Quality

Using guest posts can be a good thing if they are done right. Guest posts need to be relevant and of quality. Having links in the author/ bio section or author page can decrease your rankings if those links are not relevant, have a low pagerank or are not seen as useful or valuable.

How about getting your customers to write content for you? User-generated content is a great for  SEO and all you have to do is ask for it.