The “Starter” tier, with 1000 keyword lookups every 24 hours should be enough for anyone starting out in blogging – or even people who are quite established. It’s pleasing to see a product where they don’t seem to trick you into having to pay for a more expensive version. On the more negative side, I did feel that you’re nudged towards doing annual payment, with the monthly option kept slightly “hidden.”
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.