I don't get where all this talk of HF spikes for the HD700 came from, either Sennheiser did some finr tuning in later releases, or my hearing is just crap. I A/B'ed it with the HD800 and seriously, the HD700 is all about warmth. My HD800 and K812 has some nice highs, not bright at all and with such high treble, one tends to hear a fair bit of detail. They are quite unlike the AD2000 which, to my ears anyway, are pretty bright, almost to the point of being intolerable......almost. It creates a sense of detail as well, but somehow, it doesn't quite sound right to me. Quite fatiguing to listen to for extended period, but no such issue with the HD800 (can't comment about the AKG K812 yet as I've only just acquired it).
When you audition the HD700, just keep an open mind and try it with a couple of source setups and see if it suits you. I tried the HD700 on my Lyr + Fostex HPA4 stack and found it to be dark actually, using the HPA4 alone (it's an amp/dac combo after all) brought helped bring out some highs, but certainly not to the point where it's bright, not even close. BTW, pretty new at this, so if I use the wrong word to describe a sound......my bad.