As far as I know, they have the exact same moving armature driver as the Ortofon e-Q7 and e-Q5, they are also very similarly tuned, it seems. Here's more about them (via Google translate): http://translate.google.com/translat...8.html&act=url
Funny enough, I heard through the grapevine that the Grados are much cheaper to manufacture than the Ortofons (due to the cheap plastic housing instead of milled aluminum, etc), yet are sold at a higher price... I have the Ortofon e-Q5 and have tested a friend's e-Q7 for several weeks - they're extremely good phones. Based on looks, build quality, and price I would go for one of them instead of the cheap plastick-y Grado. The e-Q5 are EUR 219 including free shipping from Japan (at MusicaAcoustics
, where I got mine from).
By the way, in the meantime there's already Grado GR10 available - same housing, same design, even more expensive. A friend of mine is getting them, and I'm sure he will lend them to me sometimes for a listen.
Maybe I know more in a few weeks, stay tuned.