In fact, Google Suggest is the best way to find good long tail keywords that people use to find information on Google. Google admits that while Google Autocomplete (another name for the Google Suggest feature) was not designed specifically for marketing, it can deliver meaningful insights and help stay on top of trends. There are also many clever ways to use Google Autocomplete that can help you with SEO.
So whilst Long Tail Pro has just continued to grow in revenue every single year and comes highly recommended, you may want to check if all the important features are fully functioning before signing up. Especially the KC feature (keyword competitiveness) as it is so fundamental to keyword research and making an informed choice on whether or not to go into a particular niche.
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.