"I rarely get excited about SEO and SEM tools...But, when it comes to keyword research it is virtually impossible to produce a quality worksheet without software. When I have to perform the same task for my customers, the process is even more daunting and time consuming...there is now a better way to manage huge keyword lists and this tool is called WordStream."
To be able to rank in the search engines is an art that must be understood and finding the right Keyword tool that fits into your comfort zone is a must. What I mean by ‘comfort zone’ is having a keyword tool that doesn’t confuse you before you begin even searching. Some go into far too much detail than is necessary. All you need really are good long tail ‘common sense’ keywords that other marketers may have missed.
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.