I just got the K702 a few days ago, and all I have to say is that is headphone is ridiculous. It's only undergone 2 days of burn-in, so the highs still have a shade of that metallic brightness to it, but overall it's very musical. The bass and mids are already mostly there, and it's just the slight (and I mean very slight) metallic highs that haven't fully disappeared. I love it. Crystal clear sound. I can't believe it still gets better from here on.
I received the RS1 the same day, and both have been burning in since. The RS1's already fully burned in. I'm comparing every headset I have, and I think the K702 will probably end up my favorite headphone, over the RS1. I love the Grado sound. I truly do. But these K702's are just flat out ridiculous.