Having owned both (past tense, I now only have the blade from the G10 version in a stonewashed framelock, my personal favorite), I would go with the Composite again. It's cheaper, the CPM-D2 should have much higher edge retention (according to Jankerson's post, I didn't use mine enough to notice), and I'm not a fan of the aesthetics of the G10 version. The handle is thicker than your normal framelock leek, so it looks a little weird with the incredibly thin blade. Also, the G10 has no sculpting to speak of, so it's sort of blocky in my hands. The linerlock on my G10 leek was very thin and easy to disengage, which might concern some people, but I never used it for anything beyond light duty so it was an issue for me.
I do love the stonewash on the G10 Leek's blade, I will give it that. Leek's are so addictive that you'll probably end up with both anyway.