For me, personally, ceramic elements on a tool watch, or sports watch that is subjected to increased stress, is a no-go. Like sapphire crystal, ceramics is very hard, but also more brittle and will have a much higher probability to break when receiving a hard blow. I just saw a new Omega Ploprof with a broken sapphire bezel ring, after its owner had hit a rock under water. Metal will have a dent or a nick, but will not break. However, if you are - like myself - purely a desktop diver, with no intention to do some rough sports, or Mission Impossible-style gymnastics, ceramic can play out its real bonus, that of being practically scratch-proof.
Regards,
Marcus