How well do these ports handle power? Part of the magic of the macs is the OS/hardware integration...and part of the power management is really deeply embedded between applications, the OS, and the hardware.
(edit) I misunderstood your question. I have charged my iPhone in a port and have also used an external audio card that drew power from it. Not sure it behaves as well as OSX but it works.
Powersaving is not turned on by default because lots of hardware, e.g. some audio cards and keyboards, misbehave on powersaving states. macOS has the advantage of dealing with tightly controlled hardware, and might use powersaving blacklists for peripherals.
The distinguishing feature of Macs in terms of powersaving is IMHO Safari, which is an energy efficiency marvel, especially if you play videos. I don't play videos often, so Firefox is not that bad for me. Aside from this, my Linux desktop has a lot less services than macOS, so it compensates the difference. Someone should start a serious Firefox energy saving initiative. By simply tweaking compilation parameters, I am sure some significant savings can be accomplished.
Thanks! Perhaps you should write a guide with your findings and optimizations. It's sorely missing.