I'm the author. ActualVim feels pretty slick out of the box. The main issue is in parts of the Vim UI that aren't integrated yet (I'm praying for more UI customization options from Sublime Text, though the recent command palette improvements should be a great start for replacing the command line).

The actual editing should be really solid, even if you use Sublime Text features to manipulate text. It's typically very fast too, I try to beat 16ms handle time per keystroke on all platforms (so updates land within a frame).