The first one is good, and i love the second ones, but i dont like the abundance of light around his head, i would personally tone that down. Other than that, great job.
text colors are not matching.
the line through the renders head catches my eye to much.
it looks like you followed the same tut on both but added a b&w gradient to the second one.
not bad. just could use a little touch up
I like the first one, it could just use a little clean up.
The lighting on the second one is soooo messed up, it detracts from the overall quality.
Im also not a big fan of the text on either.