I really like this piece. It's a totally different look for Sauron, but it works very well. I love how the eye is staining with golden light - the longer I look at your painting, the more gold I see. I also love how the over all palette of the piece is green and gold. Again, a very unique look for Sauron. His eyes look great, as well. They seem to burn with an intensity that's perfect for someone who ultimately becomes a giant eye-in-the-sky!
The only thing I would change (and it's probably a matter of taste) are the patches of white on his arms. I know it can be very hard to get a good transition between colors, but some color there would make this piece look even better - the white visually dampens the intensity of the golden eye.
Over all, very good work!