What's the difference between Ctrl+C and Ctrl+[? The documents contain the following that I can find:
<Esc> or CTRL-[ End insert or Replace mode, go back to Normal mode. Finish abbreviation. Note: If your <Esc> key is hard to hit on your keyboard, train yourself to use CTRL-[.
CTRL-C Quit insert mode, go back to Normal mode. Do not check for abbreviations. Does not trigger the |InsertLeave| autocommand event.
CTRL-C Interrupt current (search) command. Use CTRL-Break on MS-DOS |dos-CTRL-Break|. In Normal mode, any pending command is aborted.
It seems there is some disagreement to what exactly the commands do.
Does Ctrl+C not also leave Replace mode, and how do abbreviations relate to pending commands?