I have an 8 card 1070ti rig after very carefully analyzing profit and ROI. The 1080ti is 24% on average more profitable (at 33% more cost based on your numbers). I calculated the RX570 cards as 12% less profitable and their resale was about 40% less. Over Christmas I babysat a RX570 rig (12 cards) and it made about 25% less than my 1070ti rig and took more power too. I'm not sure why it was so much lower than my calculations, but the 1070ti remains the best choice right now. It just doesn't make sense to buy them for another 2-3 weeks until the first few major shipments of cards arrive from asia. Now I just wish I'd find a container full of those on the shoreline...