no, its the best performer regarding hashrate
best in terms $/W/hs is RX580 Sapphire Nitro+
1060 3 or 6GB with Samsung mem is slightly more efficient than the RX580.
That is wrong, maximum hash rate a 1060 6Gb can achieve is 24 or 24.5 mhs at best. The maximum hash rate a RX 580 4/8GB after the bios modification can achieve is 31 mhs. After the bios mod the consumption in energy is almost identical, so the 1060 is way behind RX 580 4/8GB in term of performance and consumption.
31,5MH/s for 2 of my 570s
Zawawa has put kernels on github (he talks about in the GGS thread) for 32,5MH/s on a 480.