Overall, both headphones are feature-rich and cater to users looking for a combination of sound quality, comfort, and wireless convenience. There is a noticeable difference in weight (260 g vs NA), which may affect comfort during extended use. Impedance levels vary (45 Ohms vs 35 Ohms), which can affect compatibility and audio output when used with different devices. Both headphones offer solid battery performance, making them suitable for long listening sessions and travel. Both models support modern Bluetooth connectivity, ensuring stable wireless performance with compatible devices. The driver size differs between the two (NA vs 40 mm), which can influence sound depth, bass response, and overall audio clarity. The frequency response differs (20 Hz-20,000 Hz vs 10 Hz - 25000 Hz), which can influence how well the headphones reproduce lows, mids, and highs. Beats Solo2 and Koss Pro4s are premium wireless headphones designed to deliver high-quality sound along with advanced features like noise cancellation and long battery life. Both models feature noise cancellation, helping reduce background noise for a more immersive listening experience.

Verdict: Both headphones offer strong performance, and the right choice depends on your priorities such as battery life, comfort, and noise cancellation.