I have a lot of experience with a lot of SEO tools and i kinda like the simple but yet very complete approach by ranktracker. I get all my rankings in the blink of an eye on a daily basis. On top of that it has a KW finder, an SEO checklist, reporting for potential clients and a website audit feature, with the most important fixes for your site. It's to the point and very easy to understand. I would recommend Ranktracker to every website owner to get the most out of their SEO strategy.