DWIW I git my 1070 asap aftr the initial founders run and street prices were pretty much $429 across most lines - EVGA, Asus, PNY, Zotac , MSI, Gogabyte.
Still $70 increase sucks ass. Probably will hold tight on my 1070 for a while can run everything at 1080/60 and most things 1440 at 45-60 depending . 4k - can usually get solid 30fps. Until 1080 games can't max or 4k at better rates becomes obtainable. Probably need a cpu/mobo upgrade first. from a 4690k to something in the i7 line