I just tried the Grado line, specifically the SR-80i with comfy pads. Comparing to my HD 201:
The Grado SR-80i with comfy pads make the music more inside your head, and that is the largest difference by far. The guitar is staged and sounds better, but not extensively better. The music is bit smoother and clearer as well. The HD 201s don't have as good separation, and separation is one of the biggest differences between the two, but that difference isn't large nevertheless. Treble response was similar, with the SR-80is having a bit more peircing and separated treble but not too much more. The SR-80i had a punchier bass; I was actually pretty surprised at how awesome bass just sounds in general. Sub-bass is missing in both head phones, but the SR-80i does general bass guitar much better. The actual sound of normal electric guitar sounds quite similar, but again the guitar is stretched across the soundstage and more in your head. Metal was of course very exciting with the Grado but when ever I went back to the HD 201, I was like "I'm not really missing any thing here. The guitar just isn't in my face and the sound isn't quite as smooth, but who cares?" I never recognized any "faster" sounding tracks over my HD 201s. Nothing sounded congested on my HD 201s compared to the Grado SR-80i, even in the fastest tracks.
What is the Grado SR-80i? A headphone NOT worth $99 when the HD 201 does what it does just a little bit worse for $20. The SR-80i sounds $30 more expensive than the HD 201, not $80! In fact, I feel like if I were to buy some comfy pads for the HD 201 I'd be getting a very Grado like sound. I tried the SR-60i with BOWLS and man, WAY different sound.
I happened to try the GS1000 with the huge cups. I'm sorry but do NOT waste your money on these head phones. The level of detail people rave about is actually a clever trick because the treble is turned WELL above what it should be. I listened to them and couldn't believe how peircing the treble was, I could barely stand it! What was very cool though, was the BASS on the GS1000. If you want to hear ****ing killer bass with peircing treble the GS1000 is for you. I swear the bass sounded like it was coming from a full tube amp! And the rest of the music wasn't bass overpowered, no wall of mud, the bass stood on its own. Other than that, the music didn't sound too much better, at least for the rediculous price.
In the end, I would take the SR-80i over the HD 201 any day, but am I going to buy a 60i/80i? Simpy, no. I originally started looking for new head phones to add some sub-bass to my empty sounding HD 201s, and the HD 555s offer that extra bass. Between the HD 201s and Grado SR-80i, Grado wins, but I'm done with treble filled head phones, and would rather not make a side-grade to a Grado SR-80i with smoother sounds and bigger guitar. Between the Grado SR-80i and HD 555, HD 555 wins because it has every thing I love about the HD 201 with more detail, larger sound stage, and deeper bass. I honestly would love to have the HD 555 and Grado SR-80i. I can tell when I'm in the need for serious metal listening I would use the Grado, but I can't afford both head phones, and I would use the HD 555 MUCH more than the Grado (for music, movies and gaming).
Was I blown away by the SR-60i/SR80i? No, I wasn't. I'm kind of more like a "music is music" kind of guy, and the differences you guys point out in head phones to me are MUCH smaller. Grado may be BETTER for metal but they don't make metal sound compared to my headphones as good as a lot of users here state.