Rated 4 out of 5 stars
1) When mousing over a link RB often completes the replacement _after_ Firefox has already displayed the URL in the status bar. The result is that Firefox is showing the original URL but RB has already made the replacement.
I rely on the status bar to know where I'm going next (and if to confirm whether RB made a good replacement). The status bar must _always_ reflect RB's replacement.
2) Setting "hide delay" and "show delay" to zero results in buggy behaviour with menus persisting or not showing up at all. Reproducible by quickly mousing over and out of links repeatedly.
Firefox only update the element if I hide and then show again, the problem with that its cause blink effect in thoses element while hovering... I going to open a bug report in Firefox.