I would echo what one or two others have emphasised on here. Don’t ever lose site that your keyword seo use should never be at the expense of the visitor experience.

By all means get use various tools to get the keyword phrases, use keyword density, anchor text, LSI etc etc, but always remeber to write in a natural way which is relevant to the topic concerned.

You can have the best keyword phrases there are but if no one reads your post/article then you’re waisting your time in the long run.

There are loads of other tools you haven’t mentioned as well. Some free, others that cost. Some of them are absolutely brilliant at keyword research and also seo generally.

Check out http://www.keyword-selectortool.com

Andy