Very nice tool Rated 5 out of 5 stars
It's very good tools for SEO webmasters.
I use it about past 4-5 month and very happy.
Many "hand work" make SeoQuake for me.
About spyware. I try see source code - this opened, nothing about spyware. This pluggin use AdSpy.com. This is legitime software without any spyware or tojans.