the guitars seem fairly similar. aside from neck profile and the fingerboard inlays (the fingerboard material is different too but you stated you would take either maple or ebony). If you favor the wizard neck over a thicker neck, then I would say buy the 8670. the tree of life isn't as important.. it's mostly just looks and it may even grow on you. If you sacrifice the neck profile to get dot inlays buy buying the 8570
(plus the hardware isn't exactly black.. it's just a darker chrome), you may really dislike the way it plays... then it was a waste of money... cosmetics are important.. but it's really what you think plays the best that counts.
I will say, however, that the neck thickness of the 8570 is almost exacly the same as my 8527 7-string. the 8570 is only .5mm thicker than the 8527. The 8527 plays spectacularly. very fast, very smooth. the thickness takes a little bit of getting used to. But, I have both an 8527 with that neck and a 3120 with a wizard, and I can play them interchangibly with no problem. something to think about. good luck with your search