Both those portrait shots are excellent Robert.
I would like to be brutally honest in my critique though as this always helps me in, well life really (honest critique I mean).
Two things bug me. I have a great love for B&W photo's, but I rarely see digital B&W's that really blow me away, simply because they always feel a bit "smooth" to me. I find the grain of 400 or even 800 iso B&W film to be significantly more pleasing to my eye than digital B&W's.
So for that reason I'd vote the colour shot. Although, in the colour shot I am finding the background a little more distracting than in the B&W. If it were me, I'd be tempted to try removing the (i think it's a plant right?) digitally and see if I liked the effect more.
Anyway, I had to try hard to find fault as thats an excellent shot as I said. You've either accidentally or on purpose, either way is good haha, nailed the key elements I like to see in a portrait. Focus and DOF are perfect, especially with the wide aperture I assume was used F3.5 ish perhaps? I also think you nailed the lighting. Getting the light reflections in the eyes is also great and adds a lot to the shot.
As has been said, wow, there are some people here who know there way around a camera it seems! I better lift my game :AOK
Oh and lastly, I'm loving the snow shots. It doesn't snow in Sydney