B&W. Its probably because in the colored version, theres is alot of black, so the character doesn't stand out. I do like the colors, but it seems too simple, and the black is a bit much. Also the character is a bit blurry, so there isnt' much focus. Sharpness is the key also for attention. Giving too much blurr all over, won't focus the character well. Just looking at the eyes, makes me not want to look at it anymore.
Usually when something glows, it should be also effecting the other areas and especially in black area, alot brighter.
I don't want to offend you, but I think the artwork in grey scale is better. Well, both images are a bit blurred, but the coloured one looks a bit lazy to me. Like I said, I don't want to offend you and I will explain, what I mean. It looks like just put some colour above the grey scale scanned artwork. That's all. Correct me, if I am wrong, but this is how it seems to me.
Maybe you should take a look into colour theory. So you can advance your coloured versions of your artworks. Like, let's say, normally under the blue sky the shadows are cooler than the rest of the colours, which lie in the light. Well, in general it depends on the light settings, if the shadows have cooler or warmer colours. Nothing consists only of one colour. Light and shadow influence colour a lot and the surrounding colour influence other colours as well. You could push your work more. I think you are capable of it.
Wow, I do like both of them, but I definitely feel that the coloured one really has something else about it! I really like the way you did the lighting in the coloured version, and the colours compliment each other really nicely.