First off let me just say that I really dig your line work. It's quite strong and full of life. Both the top and bottom black and white work is superb.
As for the Painter piece I can see you going one of two ways.
If you're looking to do a painterly piece and get rid of your linework then I would suggest trying to add more contrast between your lights and darks. Take a look at the differences between the color and B&W versions of "Bomber-grrl". You've essentially removed all the inherent pop of the black and white version by using lights and shadows that are too close in value. If you were to really punch up your shadows and put in some nice highlights I think the piece would have a lot more oomph.
I'm also reacting to the loss of form and detail between the two. What I mean is the B&W version has a lot going on in the coat, suggesting folds and wrinkles, whereas the color version lacks any of that character. The hair is lacking in a similar fashion. You've gone from trying to render the hair as a volume to painting in each hair. Both of these characteristics tend to flatten the image.
Now, if you're wanting to try a new coloring technique pop that linework onto it's own layer in Photoshop (Note: Painter 6 and 7 both support Photoshop documents with layers. Just save the file as a PSD then open it it Painter.), then try doing a painterly color UNDER the linework. You might have some interesting results.
All in all not a bad first start. In the future pay attention to your volumes and use light and shadow to define your shapes. You've obviously got a handle on doing great linework. It's a short hop to translate that into doing great paintings.
These grapes taste like Fresno! -- Steinbeck