Some nice sigs, you could do with looking into lighting effects to help add depth to your sigs.
Main thing I would say though is to experiment with different fonts and methods to make them still appear in your sig, but not TOO much. Using a majorly contrasting colour makes them stand out too much and thus, kinda spoils the sig.
I like the lighting you seem to have started on here, but not a fan of the techy brushes, don't really fit with the theme or the image. Image is nicely blended into the effects though.