It'd be 10x easier to style the buttons themselves if it used html markup instead of images for the voting buttons.
Sure, the built in range of buttons isn't bad but it doesn't really fit in with a lot of themes. Not to mention the extra http requests that are wasted when we could just as well use a sprite in our own directories.
Apart from that, excellent plugin, just great! :)
I'd really love to see the buttons as <divs> though so we can easily apply our own styles to them.