BUMP for an interesting topic.
I am a big Hexar AF fan. I have owned 4 and have experience shooting it in all sorts of conditions. I have experience using an ND8 filter to compensate for ISO 400+ film outdoors, and it does *kind of* work but it won't let you reach f/2-f/4.
The other day I shot with a friend's Contax G2 and I have to say, it was a really nice camera. The viewfinder was small but that is really my only complaint about it. If you are shooting the camera in low-light, the Hexar AF will be your best bet because the shutter speed limitation mentioned above will not hinder you, but if you are looking for a camera to shoot in all light conditions with the ability to isolate focus and blur the background, the Contax G2 (1/6000 top shutter speed in A-Priority mode) is for you. Also, I am a simple lens guy-- I like 35mm for 90% of my shooting, with 28+50 filling in the rest, so the Hexar AF's fixed 35mm lens is fine with me.
This being said, I am saving for a G2 because I wont have to switch films in and out all the time to make up for the shutter speed limitation and the 35mm lens for the G2 has less distortion.
I like being able to shoot one film speed for BW and color (ISO 400) and with the Contax G2, I will be able to stick to one film speed without having to carry around low-ISO film around with me to make up for the slow shutter of the Hexar AF if say the sun comes out.