Alright. I don't like the colors for one. There's a nice golden color on him, but the b&w background just doesn't work. Same for the particle things. As well, there seems to be a white edge around the guy. I don't know if this is intentional or not, but it really cuts back on blending. Text placement and font are good, but it looks a little drab imo.
I can see what Mike means but to help the blending i personally would dup the stock and smudge the outlines then erase what you dont need maby lower the oppacity but you have improved alot!
Take the black out, and maybe this would be a better sig. Your text needs a glow or something, because it's too hard to read for starters. Your render is too big, and the background doesn't match it one bit. Always try to make your background the same(ish) color as your render.