I prefer Sublime Text 3 over Vim as my default editor with git. Here is how I set that up on my windows workstation.
git config --global core.editor "\"C:\\Program Files\\Sublime Text 3\\sublime_text.exe\" -n -w"
-n flag tells sublime to open in a new window, so this particular edit that you are doing is isolated and not a tab within an already running instance of Sublime Text 3.
-w flag tells sublime to wait for the files to be closed before returning. This is what causes git to "hang" while it waits on your edits.