Hi Simphiwes
I'm afraid this is where things get totally subjective and everybody disagrees. But I'll give you my take on the matter. Whether you find yourself in agreement with any of it, is up to you.
First, off, I've never heard any Grado set, or most of the newer high end sets for that matter. Poverty does that
I've seen mention that the SR60 sounds very unlike others in the range. I've no idea.
Many moons ago, I went for the AKG K500 after testing everything I could lay my hands on at the time. The chief other contenders were Sennheiser, MBQuart and Beyer. I dragged a CDP and headphone amp all over the place to go listen.
My conclusions at the time were:
Beyerdynamic can shatter glass. Szzibilant as all hell at the slightest provocation. The big bottom end doesn't help.
MBQuart is big and fat and comfy sounding. A "Who cares about detail anyway? Life is about rock-and-roll!" kind of vibe. Almost like a Shure product. (Can work surprisingly well for classical recordings.) There was one lemon high up in the range that was plain terrible. Weak and confused and bloated, all together.
Sennheiser is too polite, in too dishonest a way. They've always given me the feeling of having eaten too much chocolate cake with cherry liqeur and slumping in the back of a big wavey Merc, being driven through an overcast forest landscape with the heater on. Safe, but stuffy, slightly car-sick and in a haze. I'm too much of a boer for those.
The AKGs remain my weapon of choice. They have a light bottom end. Their midrange is papery, the cheaper ones more so. Top is airy. On the whole, think dry wood. But more like Pine than Teak. Perhaps like a seriously well-aged fiddle, if one is feeling complimentary.
So ludo just doesn't like headphones, you'd say. Not so. I like my cans more than most things. I could never afford speakers that give me the same detail, so that I can curse the producers about how they did the compression and overmodulated the tape, and sit in awe about how differently people can approach a piano. But the sonic differences between different types of headphones are so large, that I feel the science is still in it's infancy. So that's also why I'm being so free with the blanket-damnations and generalisations above.
Strangely, the sonic "family character" also applies to microphones made by the same companies. Usually, one just has to use whatever is available, and they all work fine. But they have character. As the price goes up, the detail usually gets better, but the character remains. I'd even go so far as to say the character of the mics has as much influence as the acoustics of the venue. Every time, for music, I prefer the AKG. Faults and all.
I wouldn't go so far as to call myself a fan of the Austrian way (AKG). Too much idiotic design in the mechanical bits for one thing. Maybe I'm a bit more rough on tires than most, but things should last for 30 years without application of epoxy and cable ties, intermittent connections etc. Still like them though.
You should find a pair of whichever you consider, to listen to before buying, even if you have to move heaven and earth. Take your CD player & pre, even your iPod along and give it a spin. With higher impedance cans (say 100 Ohm or more), just don't expect the iPod to go terribly loud, but you'll get an idea of how things are.
When you improve sources and add nice headphone amps, things change for the better, but one never gets completely rid of the character of the cans. You just have to pick the pair that doesn't depress you.
