It's very hard for any keyword research tool to find the perfect formula for Keyword SEO difficulty (I should know since i launched the new tool in my signature), because they usually use one formula/algorithm for all queries and all type of keywords.
But if you have done keyword research for some time, you know that depending on the type of queries you use, there are nuances to how you evaluate your competition. An ecommerce based keyword, will be evaluated different from an informational keyword, and you evaluate a seasonal keyword different than just looking at the seo metrics.
That's why I think the best way is to look at the top 10 results individually when you make your evaluation, and not rely just on Keyword Difficulty score to filter through a bunch of keywords, as they may miss something.
I would have agreed to this, but not anymore. The site is down again and they say its cos of Moz. When every other site including moz is working fine.
Keysearch has worked fie all day for me today. I use that, KW finder, KW revealler, Ahrefs, Semrush and Moz - a mix to chec and double check anything that looks good.
@Nick Flame , thanks for the heads up, will give that a try too.
At the end of the day, use common sense and check competition etc manually.
Never rely on just one tool suggestion.