Interesting group of portraits, I am most drawn to the last one and number three probably because the poses are more genuine looking. However. In the others, either the finger gets in the way of me really liking it or the pp, or the crop or the shadow of his glasses, or a combination of those distract me. In number two, his hands, especially, look really greasy and the skin on his face is too shiney, combined with the dirt under his fingernails, makes him look like a homeless guy with poor personal hygiene habits. I think that expression and lighting are the two most important elements in portraiture and in numbers three and five you nailed it. Good job.