In use: The camera is smoother when advancing. It is about just as simple to load. It is much quieter, smaller and denser in the hands.
The focus wheel is quite nice for adjusting fine focus. The focus throw on S mount is longer than most F lenses that I've used. I find 1/15 usable on the S3, but I also bracket when shooting that slow.
I think F-mount vs S-mount is similar to Leicas M-mount vs thread-mount line. One is practical, utilitarian, the other is more of a .. romantic endeavor. If you've never used one, you'd have to hold it and shoot it to really get my meaning, I suspect.