I had been on the hunt for a circle cutter for a long time. So many of them are bulky, requiring a blade, templates, and a glass cutting mat. Then this little guy came along. I already owned the BasicGrey magnetic cutting mat, and this tool works perfectly with it and the magnets that come with the mat!
I was cutting perfect circles right away. I like how you can fine tune the sizes of your circles, and can cut 4-12" circles. The only con I see is that you might want circles that are under 4". Even so, I think this is a handy tool and I will be using it often.