Apple - AirPods Max (USB-C, 2nd gen) vs Sennheiser - HD 660S2

These two are nearly even on the Mars Score (65.7 vs 64.2). The decision isn't about overall quality — both clear the bar — it's about which specific trade-offs fit your use.

Pick the AirPods Max (USB-C, 2nd gen) 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 active noise cancellation, spatial audio, battery life.

Pick the HD 660S2 if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight, driver size.

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

Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity tells you both are well-rounded; the differences are about trade-offs, not quality.