I do like the B/W conversion, but I'm not so sure I prefer it over the color like I thought I would; I like the 'glow' effect in the color versions. The second color image you posted is really nice as well.
For some reason whenever I do Orton type photos, I get a colour shift on the greens, especially if their is an overlap.
I assume you're using a background layer, plus one or more additional layers that have a blend mode of overlay, soft light, hard-light, or something similar? If so there's a trick to eliminate the hue shift and keep the saturation in check. Create a Curves adjustment layer in between the background layer and the softlight/overlay layers. Don't adjust the curve, just change its blend mode to luminosity. Now right click on the softlight layer(s), and choose "Create Clipping Mask". This should give you the 'glow' effect of the softlight/overlay without the color changes.