Linux

My Dell SFF uses close to the same power as my Pi, once you start doing anything with the Pi (like swap to an SSD instead of an SD card). Pi idle: 8w. Dell SFF: 12w. Neither one show up on my power bill. Both of those are less than a single LED light bulb.

Pi is great on power at idle, with nothing else going on. But it can't convert videos at a reasonable pace, doesn't come in a case with mounts, extra power, etc.

Don't get me wrong, Pi is great, it's been fun tinkering with it, a great learning tool. But it's hard to compete with a mini or SFF on a capability-per-watt basis or physical capability (standard brackets, expansion, etc).