In general, both options are suitable for everyday use including music, calls, travel, and work-from-home scenarios. Both headphones offer solid battery performance, making them suitable for long listening sessions and travel. Impedance levels vary (300 ohm vs 56 ohm), which can affect compatibility and audio output when used with different devices. The driver size differs between the two (38 mm vs 70 mm), which can influence sound depth, bass response, and overall audio clarity. The frequency response differs (8 Hz -41500 Hz vs 4 Hz - 100000 Hz), which can influence how well the headphones reproduce lows, mids, and highs. Sennheiser HD 660S2 and Sony MDR-Z7M2 are premium wireless headphones designed to deliver high-quality sound along with advanced features like noise cancellation and long battery life. Both models support modern Bluetooth connectivity, ensuring stable wireless performance with compatible devices. There is a noticeable difference in weight (260 Gm vs 340 Gm), which may affect comfort during extended use. Sennheiser HD 660S2 and Sony MDR-Z7M2 offer different noise cancellation capabilities (AMBIENT vs NA), which can impact how effectively they block external noise.

Verdict: Choosing between Sennheiser HD 660S2 and Sony MDR-Z7M2 depends on whether you value better sound, longer battery life, or enhanced features.