I moved to the F100 about 15 years ago. I liked what it offered, and did not miss what it omitted, so much that I bought a second body for storage should my primary F100 ever break. The cost of purchasing a mint condition 2nd body was far less than what any repair would cost me. For its lighter weight and less durable potential, I still consider the F100 the superior camera over the F5/F6 models for practical, non-commercial, daily use. The one fair knock on the F100 is that the latch holding the back closed is plastic in part, weak, and not that hard to break. For years, NIkon had run out of parts and repairs for this issue, which significantly devalued the body once that became well known. More recently, enterprising soles have been offering after-market repair parts for that latch, so at least it can be repaired if yours fails.
The F 100 body is a light weight Magnesium.. The EOS 3 is constructed of glass-fiber reinforced polycarbonate with aluminum inserts around the aperture area with exterior panels of rigid engineering plastic. I chose the Canon because i felt it was better overall in terms of metting, 45. Focusing area with 7 cross type as opposed to F100 5 segment focusing points closer to the center. If i werent into Canons the only other System i would be into is Nikon. Generally you cant go wrong with any of the major 35mm camera systems bottom line theres really not a whole of diffrenence, just a metter of preference and budget. They are all Good.
Cs stands for "Continuous Slow." It's a slower frame rate of something like 3 fps, but I believe it can be changed in the custom settings menu, but like you, I haven't really monkeyed around in the menu system on my F100.
