I agree with Vero on this, it's good but all of your sigs seem to be relatively the same thing - same colors, same size, same general effects (over sharpening of the render with brushing and blurs) and the text is relatively the same as well.. small on the side of the render usually either glowed or relfected..
I'm not saying it's a bad thing to be consistent but I really think you could broaden your style and try new things. Read up on some tutorials to learn new effects and styles to incorporate into your designs.