I have one and I love, love, love it. Mine isn't magnetic. It uses sticky tape to attach base/holder and then the light slides into that. It is removeable from the base so you can remove it if you have a case/cover and the light is in the way.
It is wonderful that I can point it right at the needle, very clear clean light and if I am trying to pull out stitches on a hard color to see, I just move it so it is pointing at that work area. I bought an extra mounting bracket also.