The claim that they're freakishly bright might come from people who don't know how to wear Grado bowl pads properly (they're supposed to be on the ear not around it- and I also suspect that incorrect placement on the dummy head is what's gone wrong with the response curves on Headroom, which show a substantially bigger upper-midrange rise than what I hear from my SR80s.) I now have Ety MC5s- designed, as with all Ety's, to be very neutral- and my SR80s are only a hair brighter, and overall very similar in timbre,
much more similar than either is to several other cans I've heard/owned. I take that as independent confirmation that Grados actually are more accurate than they're given credit for around here (as opposed to, by lots of audio reviewers over the years.
Recent example.)