Withings - ScanWatch 2 vs Xiaomi - Watch S4

The ScanWatch 2 is the clear pick on raw spec strength, leading by 8.7 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.

Pick the ScanWatch 2 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. The biggest gaps in its favor are battery life.

Pick the Watch S4 if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are display size, weight, cellular, among others.

Both ship with comparable ecg, spo2, water resistance, so those specs don't separate the two — focus on the differences below.

Bottom line: the ScanWatch 2 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.