I would like to know what is the best tool out of the whole suite used to analyze my own sites. I know Seo spyglass is for competitors. But is there a better way to use it to gather data on your own sites

You can simply start a project for your own site with SEO SpyGlass and analyze your own backlinks. In order to analyze your onpage optimization and keyword densities you need to use WebSite Auditor.

By the way today a major update is released in beta for WebSite Auditor and it will let you analyze your site in ch more detail (internal links, keyword densities, broken URLs and much more) - please stay tuned