They're kind of creepy, but for the motion blur, they do create flow, however, don't get too crazy with it or else it will make the entire picture look distorted, you may want to turn down the opacity on it a bit. I like how you square out the background and have the render go outside of it. For your current sig, the blue color doesn't really blend in too well with the render, perhaps if you used a dark gray texture and a green to match it, then it would blend in better. For the background on it, you may want to try to grayscale it then make an overlay layer and create colored light that matches the render, or vice versa with the render, because the orange light on the right side of the render doesn't blend in too well with the render. If you're using photoshop, you should try to use lighting effects on render to make the light on the background reflect on the render, to make it look more realistic. Overall I see great potential. =D