Too bloated, too unstable, too insecure.

Will just reboot all the time and whore memory. Way more susceptible to malware.

Would guestimate the PC (with no GPU) to pull maybe 100w assuming an average load of 20 ish percent. - 40 of this would come from drives (about 10w each).

This would be about 2.4kwh/day or in the UK, around £0.70 on a cheap tariff (or £255 a year). Obviously these figures vary massively depending on power cost per kwh in your region

Sounds like a 24port none poe is the one for me then! Thats only 10w more than the mikrotik