I’ve had SpyFu for about 4 months now ($38 a month if you don’t have a discount). The idea behind SpyFu is to give you keyword and competition data before you jump into a niche. I’ll generally use this tool when I first think of a niche to see roughly how expensive the niche is going to cost me per click as well as to see what some of the competition for that niche is bidding on. This tool is by no means a complete “keyword” research tool although you can steal large amounts of other people’s keywords they are using to advertise their site. I would highly suggest you use SpyFu with another keyword research tool like Wordze.