I use keywords for programs I sell, I need to know what possible terms people may use to find that program so they can find me. I am no expert on all the tools that are available, at the moment I use google tools to find keywords, you can put in a term and it will give variants and related searches, it perhaps not the best, but its free, and I don't know whats on the market, but it does have a failure. If you have a bunch of lists of keywords and want to know how they rank in searches next to each other it falls, down, it only takes a keyword, and then shows variants of that, it does not enable you to put in a bunch of keywords and have them be ranked in order of searches to see how they fare against each other. So that's what I'm after, I want to put in my keywords, and have them ranked in order of searches, can anyone suggest a free tool or service, or even the paid ones if nothing free does this job.
Try semrush.com. The website extracts keywords from a website (Yours or your competitors') and shows number of searches for those keywords. Very versatile tool and free. As for the paid software, I use Micro Niche Finder (excellent for long-tail keywords) and Market Samurai. Both pieces of software are well worth the price. Hope it helps.