Because of the 95, I'd rule out the Hexar RF. It's better for shooting up to 50mm. Perfect viewfinder for a 35, though.
They have quite different shutter sounds... both are quite noisier than a Leica. the Hexar RF is more automatizated, the ZI being more mechanical (if that makes any sense). The Hexar RF sounds like what one would expect a camera do sound like, the ZI shutter sound might be perceived as something else making noise. Granted, I've shot with the Hexar RF inside a bus and didn't bring any attention, and got a shot that I like a lot in the process. I've met a guy a few days ago shooting a ZI also in a bus and it the shutter sound wasn't distracting. But I'd say both are on the same noise level, albeit being different.
1/4000 can be useful if you enjoy shooting at wider apertures, though an ND filter does the trick. The automated advance and rewind are cool features but I've found that they don't speed up the shooting process significantly vs manually advancing and rewinding film.