The only thing remotely biased was my song choices. If I had picked one or two less bass songs and an extra mid-centric jazz or orchestral song the HD650 would have won the face-off. In fact, even if you were to take into account only the sound qualities in my ratings you would see the HD650 barely edged the D2000 for me. I think I even mention about the HD650 sonically being the better headphone.
Timbre, resolution and instrument separation are all largely qualities of mids and treble. Just as bass impact and extension are two very important categories that a closed and famously performing D2000 would excel in, the two soundstage categories are two qualities that almost every closed headphone would fall short in compared to an open headphone. You could argue semantics, but realistically the categories I give are all arguably more applicable to real-world sound and technicalities.
The D2000 went in as my favorite vs the HE-400 and came out losing by quite a margin. There is no 'bias from current favorite' as you speak of. It's more like 'HD650's overall performance is horribly overhyped and didn't satisfy my requirements.' People like to argue that it truly shines with x high dollar fancy amplifier and equipment, but at that point anybody who's sane would be better off getting higher end headphones and achieve even better results. There's a certain lore behind the HD650 on head-fi that I just don't understand, but that's not to stop me from saying that it's one of the best headphones on the market.
Reviews are subjective just as your opinion on the HD650's comfort is subjective. I've overheard lots of people saying HD650 was either one of the most comfortable or lesser comfortable headphones they've put on their heads. One thing I think you will never find however, is someone saying a Denon lacks in comfort. It's almost universally agreed upon to be a top notch in the comfort department and my experience with the D2000 definitely parallels everybody's thoughts on the matter.
Let the 650 followers whine about it though, that's fine in my book.
