Nice cuts for both, although the second is a little choppy. Then again, if use renders in sigs etc, you should know how to blend them! For the smoke, why not duplicate the layer and on the bottom one, smudge and blur the smoke outwards a little... that might give the smoke back its original form... just a thought!
First one= Sweet. Second one= Not so sweet. All in all, nice cuts. The second one looks scrunched, and isn't near the quality of it's older brother up there.