I had S0-S3 in aluminum, S4 in stainless, S5 and S6 in Ti, I would say for cycling the weight doesn't really make a huge difference coz I'm grabbing onto the handlebar, for running and other activities, the SS was kindda too heavy for me, obviously the aluminum is the lightest. When I went from SS to Ti it was noticeably lighter, and I can tolerate its weight on my wrist on casual runs. For more serious runs and workouts (not a ton of those now when all races are cancelled), I still wear a Garmin, and carry the AW in my FitBelt for emergencies.
To me the Ti is sorta the sweet spot in terms of weight vs durability and style, but unfortunately it's also the most expensive of the 3.
