When I finally made the decision the get Long Tail Pro way back in December of 2012 – I honestly had no idea how much this one piece of software would impact everything I do online. I knew that it would help me find more and better keywords right off the bat. But I didn’t know exactly how much it would positively affect my ability to actually make money online. I can say with confidence, that Long Tail Pro is the one tool that has made the biggest difference (by far), in my ability to get traffic to websites and actually earn money online.
SEMrush is a very useful tool for both researching competitors when starting a site or for growing an established site. I really like to find weaker niche sites that still seem to be ranking for lots of keywords; SEMrush helps me see what they are ranking for and what I can potentially target. You can also see what keywords you’re on the cusp of ranking for with your established site - another very useful feature.
Long Tail Pro is a keyword research tool that helps you quickly find low competition keywords for your website. In particular, the tool is built for people doing SEO (search engine optimization) as opposed to people doing paid ads (Google Adwords PPC). I'm sure there are some advertisers that use the tool for paid ad keyword research, but the tool was built for SEO keyword research.