[statico]

Instead of Esc you can use Ctrl-C without any delay. I learned this years ago when the latency of a satellite Internet connection would interfere with Esc and Meta.

And, if you remap Caps Lock to Ctrl, Ctrl-C will be easier to type.

This works 99% of the time. The only exception I know of where it performs differently is in operations on a visual block (not visual line) selection -- hitting Ctrl-C only applies changes to the current line but Esc does what you want.

[notJim]

It's not well-explained in this article, but the problem is that when press a key like O in normal mode (to insert a line), vim will wait a certain amount of time to see if there's another key of a sequence about to follow. Reducing this timeout or disabling esckeys will reduce the or eliminate the wait time.

[strager]

10ix<ESC>

vs

10ix<CTRL-C>

^C cancels the current command, where ESC exits insert mode.