What is your maximum budget on a card? Although many will say go with used as they have been lucky, in the long-term used cards require service much sooner than new retail. Having said that, there is a different price point....Investing in a 1070 at this point, I believe to be "pointless"....The 1070 and the 1070i are quite far apart in max. performance, and you don't want to be stuck in a year's time with an out-dated, out-of-favor card. Personally, .I made an offer to pcsabre on ebay (they accept offers) when the price was a big lower, for 359 bucks for a new 1070 ti zotac mini card. It arrived and it is fabulous. Overclocked like a breeze, does not overheat...in fact performs as good as, or better than a stock or slightly overclocked 1080 without the excess heat. Can you wait a bit longer? I think you're going to see prices drop further before the holidays, and you can pick up something NEW. Nothing quite like it. Good luck.
By the way, my graphics score in 3dmark was higher than the 1080, of course with an O/C!
I would like to keep cost between $250-300
The second and last link seems to be a good choice to consider.
If they are working proper, i don't know though.
I just purchased two EVGA 1070 SC off Ebay today for $247 and $265 brand new. You can get a new card off there instead of used if you keep looking