My group ordered 2 pieces of V6 classic dual & 2 pieces of V6 vivid dual. They are DIY headphone amps; we tried other op amps such as 833, 4562, 2134 etc. I personally love the classic (red) version. It brings the vocal voice upfront a bit more. Vivid version plays well for all frequencies and more analytical. My friend returned from Japan with Muses 01, 02 and 03. I found V6 is a little bit more capable of handling big group performance than Muses03. With lots of instruments and vocal put together, V6 has everything under control with same level of clarity. Many op amps would render that a bit “messy”. For comparison, I listened to “Another day of Sun” from the Album “La La Land” and the chorus part is obvious.