Could you give some example sites? I'll look into it. Also, if it only crashes on a small set of sites, you could selectively disable Vimium on those sites via the browser action icon.

Facebook for one. Anything with a large number of anchors and forms absolutely kills the performance.

That's odd, I've never had a problem with FB. Does the performance get hit right when the page loads, or only when you press a certain command?

They're mostly internal corporate sites. Is there a way I can collect information (stack traces, etc.) for you instead? I didn't see any easy way to get postmortem data on a crashed tab.

May be an issue with your computer / config. I've been using Vimium for a long time and have never had it crash anything.