Excellent, and gives a performance boost just as great as advertised. I've giving it 4 instead of five stars only because it also introduced instability into my particular setup.
My testing suggests that the normal VaM problem with the Unity garbage collector crashing when there are too many vars/morphs, is actually worse with this patch in place.
For anyone with less than 5k vars, you may never notice anything, but in my setup with 10k+ vars, loading without this patch is slow as molasses, but it works 90% of the time. With this patch, most things will load faster, but every scene carries about a 60% chance of triggering the GC crash, with a higher chance for mocap or more complex scenes.