I think the first one has a lot potential.
If we strictly talk about light, there are lots of improvements that I can point out. First off, if you're using continuous, remember that 100 watts of power will give you roughly 2 watt seconds of light at 1/50 shutter speed but the lumens will be quite low. If you're using flash, you'll get the full 100 watts of light because of the instantaneous pulse that you will receive (up 1/1000 shutter speed). You can read more about it here:
Shutter speed does not affect flash exposure
Now when you use a hair light, depending on the style you'd want, it would have to be a pretty powerful light if you're not using flash in order to get that light ring we see in professional photographs.
I've been in your position before and it comes with time. You'll learn how to position the light and how to pose them right depending on their figure. One thing I'd suggest it try keeping the catch lights down to one if possible. Two like the ones you have in both pictures are a little weird.
Next, you do not have white highlights in either photo, mostly grays and blacks. Next time you try black and white, make sure you have a good spectrum from black to white.
Be careful with the over sharpening as well, you don't want to cook his face.
Lastly, if you plan on doing pure black background, try to get him in another coloured shirt, something lighter so we don't lose him in the background!
My opinion but it's just helpful pointers