So while the RS-60s are on their way to NYC, I thought I'd just share my impressions from the time that I had with them. I'm a rather shitty writer, so I'll keep this brief.
I've owned HF-2s for a while now, and they're my mains, so I'd say that's a fair reference point. I never bothered with any critical listening or any of my familiar test tracks. I did mess around with the pads, though. As expected, I stuck with the flats. Compared to the HF-2s with flats, they're not as dark and don't have as much midbass bloat. I don't feel comfortable saying the sound is more neutral or balanced; it's just different. Resolution is definitely better on the HF-2s, presumably due to tighter spec'd drivers. The RS-60s were no slouch, though. They really sounded good to me... maybe $200 good? Wish I had a pair of SR225s on hand to compare. I guess that's a testament to the Grado driver line, as well as the importance of frame and pad quality. Oh yeah, they were also significantly lighter and more comfortable than the HF-2s, which are significant advantages in my book.
I do kinda wish I had tried some critical listening, but that's really not something I like to do at home. I mostly just listened to shitty death metal as usual, and I had no real complaints tonally. I bet they sound pretty sick from a nice balanced rig.