It's less than stellar, but still a lot better than the defaults.

I think the content and the controls should be kept separate without messing with the other, that applies to websites hijacking the scrolling as well as others trying to do creative Vim keybindings. I wish Vim browser plugins were comparable to a solution like qutebrowser though, Surfingkeys(which I use) is pretty good but the input delays of those plugins are frustrating.