Fascinating! That is EXACTLY the same experience as i had. I really, REALLY like Vim, especially because it means i can have the same development environment at home and at work. But Vimperator soon lost its shine. For the exact reasons that you said, plus on Linux it overrides the copy-paste behaviour and introduces something called a PASS-THROUGH which is confusing as anything.
It’s also what it *doesn’t* do like ‘u’ for undo in a text field.
Last night i uninstalled Vimperator but quickly realised how much i’d come to rely on it for some things, like ‘t’, ‘y’ and ‘gh’. It was disappointing to be without those. So i’ve installed it back again but made some tweaks in my ~/.vimperatorrc file.
The ‘awesome bar’ behaviour is well worth having if you don’t already use it: http://www.developernotes.com/post/Vimperator-Tip.aspx