I have been using and have found several of the services for a few years now and have had some fun playing with their tools. In many cases it takes the leg work out of researching targeted keywords.
SpyFu sells you on the fact that you can use your competitors hard-work and research to your advantage. What if your competitors screwed up? What happens when you copy an entirely faulty SEM Campaign and have to start from scratch? Sounds like a great sabotage technique if you have money to blow – in reality, SpuFu is a very helpful tool.