Whats the difference between ServerFault and SuperUser? Aren't they both for SysOps questions? Wouldn't it be prudent to have a mission statement for each site clearly visible?
The FAQ for SU and SF contain the mission statement for either site:
Super User is for computer enthusiasts and power users....
Server Fault is for Information Technology Professionals needing expert answers related to managing computer systems in a professional capacity.
If it involves managing servers, in a professional setting it goes there.
Most computer questions, outside the stuff you shouldn't ask on SE anyway (purchase recommendations and such) would fit here. Questions involving PCs, home networking and tablets are a safe bet. If it's a phone, you'd be better off on the Android or Apple SE sites.
SF, on the other hand, is a good place for questions which involve system administration. It is very helpful to get to understand their site culture, realize that these guys while occasionally cranky know their crap. If you ask stuff that involves wrangling computers, in a professional setting, and chances are you will find someone who happens to know the material at hand.
It's a good place to ask questions where, you've tried and documented 90% of the problem, are still stuck, and need a little push. It's not a nice place for folks who want to be spoon-fed. It's just how they roll.