Like vimperator, too slow to feel usable. The delay in hitting F to getting links is way too deep into human perceptibility to be anything other than irritating.

The highlighting drives me mad too, and no I don't care if it can be shut off. The slowness already killed my enthusiasm.

Is there something about how Firefox interacts with plugins that vimperator and now Pentadactyl can't seem to get the performance down?