If you can do it, go for it. You have allot more freedom to do things with a 1070, than a 1060.
eg. if you ever decide to upgrade monitors to a higher resolution or hertz
1070 is better than the 1060, hands down. If you can get the 1070 pretty close to the same price as a 1060, do it (unless it's some weird second hand deal, then I wouldn't be so sure)
If you can do it, go for it. You have allot more freedom to do things with a 1070, than a 1060.
eg. if you ever decide to upgrade monitors to a higher resolution or hertz