The price I saw for it was $200 on newegg. For the 1070ti price I saw was $450 and would be mining neoscrypt or equihash. My calculations could be a bit off but so far it seems the 580 would ROI faster?
RX 580 cards start from $250 on newegg, and that's for the most basic 4gb versions. Decent cards with decent coolers are closer to $300, and the 8gb versions are more than $300. Current high profits from these Polaris cards are all from ETN, which is a new coin that might go down really fast. After that it's back to ETH, and you're not likely to get 30 MH/s (as whattomine suggests when you select rx 580) from the cheapest 4gb rx 580 cards cause these days they often ship with weak hynix and elpida memory chips that you're lucky to get 27-28 MH/s from. So it's less than $1.5 a day per card.
Some of the 570 cards have been hitting $229 on Newegg, but nothing consistantly below that other than refurbs or open boxes - so far.
Might change over the next month though, AMD card pricing IS dropping slowly.
You CAN get the Sapphire "mining" 470 cards pretty consistantly at $260 or $279 - seems like ONE of the models is always in stock lately - and those have VERY good cooling.
4GB cards you're doing good to get to 28 Mhash/sec on ETH AFTER a BIOS mod - doesn't matter if it's 470 480 570 or 580 on that.
The other thing to keep in mind - the BLUE WHALE in the room - is that ETH goes Proof of Stake sometime next year if they stay on their current plan or semi-close - at which point profitability of pretty much ALL GPU-mineable coins will quickly collapse as those 4 MILLION or so cards currently mining ETH (mostly AMD) look for new homes.
On the plus side, card prices on AMD cards should ALSO collapse at that point as a lot of "marginal" miners find out that they're unprofitable and end up dumping used cards.
Yeah the whole eth imploding the gpu coins is a bit scary and is probably going to deter me from buying more cards for the moment but another card with a promising ROI is the Vega 56 cards able to push 2000 khs on xmr which puts it close to $5 a day if my calcs are right.