I think people's aresenal of keyword research tools are mostly the same: 1) You need a tool to examine search volume, most likely Google Keyword Planner 2) A tool to help you generate more keyword ideas. Tools that work with the search engines' autosuggestions are very popular such as KeywordTool.io and Ubersuggest 3) Then people might add a tool broaden the depth of their data, maybe including something like Google Trends or Moz's Keyword Difficulty tool.
How do I know that the KC score measures competition accurately? When I first started using the KC feature – I didn’t know for sure. But I’ve been using it since December of 2012. I’ve published literally hundreds of different articles (in different niches) around keywords with low to medium KC scores and I have a pretty good feel for the accuracy. More than 5 years of successfully ranking for low competition keywords has convinced me to completely trust the KC scores that are calculated within Long Tail Pro.
As for the history of the company, as I explained, I created Long Tail Pro back in 2011. At the time, I was creating tons of niche sites and was doing alot of keyword research and content creation. I was trying to figure out what types of keywords would rank quickly in the search engines, specifically Google, and I was frustrated with the other keyword research tools (in particular Market Samurai) out there.