Which is exactly why I'm having such a hard time choosing between the two. They're both excellent
But now that I've spent a lot more time comparing the two today...I think I'm now starting to lean towards the H6; I think their tonal balance is more even, which I feel works better for all genres. They sound closer to how I would think a recording is supposed to sound. I've come across a lot of cases where the bass of the 99 Noir is a little too much. The mids are better on the 99N, but they're not THAT much better. They sound fuller, but they also don't sound a smooth. I suppose the 99 isn't stuffy really, I think now that I've gotten used to them that's gone away, but they still sound less clear than the H6.
I also don't think the new original pads that come with the Noir are the same as the pads of the original 99C. They don't line up with Tyll's original measurements and they sound almost as bassy as the current Classics pads. From my understanding, the original 99C only has a slight bass emphasis.
Anyway, they're both excellent, it's just that I can only pick one to bring to work with me on the daily lol