I recently decided to go with ahrefs after using spyfu for a couple years and trialing secockpit. I was a moz client for awhile too about a year ago. I found spyfu data to be sketchy (or just plain wrong) fairly often, and moz, I don’t know, just didn’t seem like they were really into supporting what I wanted to know. secockpit was achingly slow for a trickle of data. ahrefs isn’t nearly so graph-y as spyfu, but they are so blazing fast and the data is so deep. I enjoy it a great deal, even if it is spendy.
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.
Yes solid keyword data dramatically changes the game as far as rankings go. I have seen many tools that provide Cost per click stats and meaningless charts that confuse most users. the data Jaaxy provides helps drive “organic” traffic to your site on a consistent basis which will out perform PPC sites every time. I like how you say thinking like the end user, as I feel that way when I search. I dive into what people are looking for and it really helps drive content idea’s. I have seen great results from that.