I tried Surfing Keys way back when I had to give up Vimperator, found it insanely laggy (like, 5 seconds just to open the command prompt; no idea if it's been fixed). I've used Vim Vixen since then [0], which has almost the same defaults as Vimperator did, for the things it supports.

[0] https://github.com/ueokande/vim-vixen