I think 1080 ti not better choice for GPU
Not better - I agree.
Simply THE BEST!
ROI is rather poor, 1060(3) is the best. Just maximum cost and hashrate. It`s the best choice if you have hundreds of cards and have no place for them.
If you ignore ETH, 1060/3 are about as good as 1070Ti, 1080 and 1080Ti on price/hash. Price per slot is also a factor - you can build a 6x1080Ti rig instead of 18x1060 and still get similar earnings.
The only upside of 1060 is the ETH hashrate, assuming that you get the good memory. The 3GB effective barrier is within months for 1060/3 (check with claymore's --benchmark), so after that you'll be forced to mine other coins.