I just got the ATH-A1000z recently, and think they're great! I've seen complaints about people who don't like the 3D wings comfort-wise, but tbh these are one of the most comfortable headphones I've worn, up there with Sony MDR-1A, DT880, and other big-cup Beyers.
I feel like whoever doesn't need to use them as portable will enjoy these greatly! Very precise bass with lots of extension. The highs are a little accentuated, but very detailed.
No idea how they compare up/down the line to 990 and 2000, but the 1000z on their own, in my expreience with other closed-backs (Beyer T5p, Oppo PM3, Denon D7100), these are pretty much the clearest/most natural closed-back in this price range. Doesn't feel like there's a tilt in the frequency response, or an obvious exaggeration of any region (maybe people who are more used to bass-heavy headphones will take a couple of days to get used to it).
Only other closed pair that doesn't cost two livers I've heard described this way is the new Neumann NDH20's, but they're a bit more expensive, and way less comfortable based on reviews: shallower cups and a lot of pressure on the head - which I guess is to be expected purely pro-focused montior type of headphones.
I didn't realize the super-long cable wasn't detachable, which is a shame since my intended use is portable, so I am selling them now (see my
FS thread).
Other than the cable being fit only for inside non-portable use cases, great pair!