Reading about 1070 -makes me feel like buying two 1070 is better than getting 1 x 1080ti

For example 1070 guys are getting ~ on average 400-450 sol - with 1070 single out of box. The 1080ti is getting 700-740 with +150 core and +300 memory.

Skein 1070 are getting 450-550 - 1x 1070

and 1080ti  get 900-990 - with overclock.


Cost wise 1080ti is around what 900-1k

Dual 1070 similar cost ?