I do enjoy the competitor analysis and keyword research on SpyFu. It's been a great tool to bring into meetings and present to clients to give them an idea of what they should be ranking for and what a realistic ad spend would be.
I feel that there are a few flaws when it comes to actual rankings. It's often hard to tell which geolocations these are rankings are from (United States, Pittsburgh, where I'm standing, radius around me, etc.)
Do your research and really determine if this is the best product for you. If you're new to SEO or extremely experienced, I would suggest exploring all options. SpyFu is very good from a keyword building and analysis standpoint. It's extremely effective, but has some hiccups.
I am using SpyFu to monitor what keywords my clients should be using and tracking ranking progress from there. It's helped paint a clearer picture to my clients as to what they need to be focusing and spending money on.