1) SEMrush - I believe that among all the 3rd party software, SEMrush has the largest keyword database. Their search volume data is pretty accurate and aligns with the Google keyword planner. Also, based on the type of content that needs to be produced (i.e. informational, transactional, etc.), one can utilize different filtering options available in it.
Are you looking for an efficient way to research keywords for your website? Do you want an easy way to find the best keywords to rank in Google? Do you know how to track how well your website is ranking for your target keywords? Long Tail Pro is a keyword research software that allows you to do detailed keyword research with a user-friendly interface. It provides really valuable, detailed information to help you to choose keywords to focus on, and even find available website addresses based on these keywords.
For a long time, I wanted to develop a tool for content marketers that would assist in the process of coming up with blog ideas and subjects. Upon researching developers for this concept I had, I stumbled across Long Tail Pro, and realized instead of developing a tool myself for fellow bloggers and content marketers, I would throw my support behind this one.
It would be great if you can provide comparative analysis of this tool with Google Keyword Planner. Since you’re using this tool so you can provide best comparison. One differentiation which I understood is that this tool works for yahoo and bing as well whereas Google keyword planner works only for Google but Google being a dominating search engine, gives the highest returns, so only this reason may not be enough to buy it.