I don't like the green border, or the green text in the bottom right corner. That, and the stuff you have all over in the sig looks a bit low quality.
Otherwise, it looks alright. The render was fit in well.
That background is waaay too busy and there's almost no definition on the render. It looks good when I kick my eyes out of focus, but only because I like green and black together. heh
There's no depth, or real concept. Look at some tutorials, and take pictures to use instead of brushes, or if you like brushes Qbrushes.com has a lot of nice ones.