This is my opinion about ATH-M50xSTS XLR compared to some other headphones & headsets that I have.
Sound quality
Is always very subjective and I think that there's no bad or good: they just sound differently -by keeping price range in mind. In short, if I would say I like (or dislike) the sound, then that means absolutely nothing for others -because tastes differs.
Microphone
Is very good and if compared to typical "gaming" headset, the difference is noticeable -in my opinion, it's even better than AKG C555 L (also condenser). In short, I can hardly imagine a better mic on headset.
But don't expect the same "sound" as we can get from standalone condenser microphone.
Comfort
Headphones are like shoes: even two different pairs have the same size, that doesn't mean that we find both equally comfortable. "They look good" is worth nothing if we don't feel comfortable wearing them.
ATH-M50xSTS are not comfortable to wear for a longer period of time (more than 1..2 hours).
Main reason for that is, because ear cups are too small for average human ear size: padding inner hole ellipse is only 5.5x4.5cm! -compared to this, even cheapo Logitech G230 is much better. Because of small size, there's quite a lot of clamping pressure on ears. Headband is ok, though.
For comparison: Sennheiser/Epos GSP-370 and Sony WH-CH710N are much more comfortable.
Conclusion
I'm not a gamer. I bough this headset for only when microphone is needed (for making Youtube content and similar) and so I can say I don't regret my decision -I only hope this headset to last long.
Note: Headset cable pair is split to two separate cables at the end. Make sure that the distance between microphone (XLR) and headphone (jack) socket (on mixer or audio interface) is not bigger than 16cm!