If nVidia ever releases el capitan drivers for polaris, these will be very useful.
My old mac pros have 2 pcie power connectors, and a 225w limit on pcie power. They currently have one "big" (e.g. 680) gpu and a gt640 running. I would love to swap that 640 out for a 1050. I don't have another power connector (unless I hang a second power supply).
No overclocking on the macs, so no loss there.
If you have the power (electrical), I would definitely think the 1060 provides more power (compute) for the price.