I use a Drift HD at the moment, it's pretty good as far as i'm concerned, not a bullet camera but pretty small, half the size of a GoPro although outright the GoPro does have a better look to it.
Here's a link to some early footage, ignore the audio as the mic is crap and have yet to get an external one. Overall I'm happy with it as the price was less than £200 delivered from Amazon.