I see where you were going with this, but I think that it could have been executed better. Put the Render on top of the brushes and fix the text up. Also, lower the opactiy on the clouds and maybe put a little color into it.
This looks alright except for the text. Fix that and I think you have a solid looking sig there. Try to add more color to the background too.
Yeah, it's all really good except for the Text IMO. Kinda gives me the feeling like hes running in the snow, not sure why. Looks real good though.
what PPE said, work on the text a little more, I like everything else though. Maybe make it a little less mucky and add some more color and brightness to it.