Metric, because that's the international standard now. The two main arguments I saw for imperial were "that's the main thing used in my country", which is a great way to just isolate yourself or make yourself feel superior to others (and thus the United States never learns from anyone else), or "it makes more sense/it's easier to use", which is very subjective. I find imperial much more incomprehensible because I'm just not used to it, and metric makes sense to me. My general experience with non-standard stuff in multiple domains (not just computers) is how much of a mess it causes in communication, so I will settle for the units that the most people in the world use, metric.