The dual-density feel is what sold me — the outer layer actually slides a bit like skin instead of feeling like one solid piece, which makes a big difference. At 17,5 cm it's substantial without being unwieldy. Easily the most realistic one I've tried.
I was skeptical about the "real skin" claim but the dual-density really does let the outer layer slide over the firmer core, which feels surprisingly lifelike. At 17.5 cm it's a good size without being intimidating.