I use tridactyl and it isn't bad. I use the standard hotkeys to navigate forward/backward or to switch between tabs (unless I want to move to a far-away tab then i'll use 'b' so I can type in it's name to select). Because, as you said, the extension hotkeys don't work while the page is loading.

However, it works great for what I mainly use it for-- navigating up/down a page, and using f/gF/F to select links and open them or open in a new tab.