If you are using Package Control, send your friend Package Control.sublime-settings. In fact, the easiest way to transfer settings between machines is to move the User package between machines. This, in combination with package control, makes setting up on a new machine relatively quick and painless. The only issues your friend might have is mismatched key binding or other system specific settings. These files have the notation some_name (platform).extension. Other than that, I wouldn’t forsee any issues (unless you are using OS X specific plugins).