Summary: These are a fine listen, no question. It is only when pitted against the Senn 600's that their colorations become apparent. They are a bit on the dark side of neutral and over-romanticize music whereas the Senn's are more neutral and give back what they are given.
Summary: RS-1 has faulty presentation with lost of neutrality. Though the bass is full and warm, it is not as fast and controlled as 600, let along Stax. People may find the distorted presentation easier to listen but since I go to concert often, RS-1's intepretation is not acceptable for classic music.
Summary: I recently did about a two-hour A/B test between the Grado RS-1's, the SR-325's, and the Sennheiser HD600's. Amplification was a Creek OBH-11 (I think that's the model number) from a CAL DX-2. I really wanted to like the Grado's, but I honestly thought they placed last in my comparison.