They are becoming more comfortable. But they're one notch under HD598's which truly can be forgotten about when wearing.
My mate had a listen to the X1's, he has 558's and said he wanted buy X1's.
We both find certain drum impacts very sharp, almost piercing. Whether its just more resolution that I need to get used to i'm not sure, some might find it fatiguing.
I only have one pair of portable closed headphones, the Beyer DT-1350 facelifts and the X1s feel closed in terms of bass response like the Beyers but open in soundstage like any open phone.
I will say that the sound they produce seems to come from right inside your head so not quite as wide a stage as the 598's.
They isolate external sound very well, with 598's I can hear PC fans even, with X1's I can't hear someone speaking at normal volume levels.
They leak sound similarly to HD598's however.
To reiterate what others have said, these are worthy of their RRP and anything less than that can be considered good value.
They happen to be the best headphones I have ever heard (I've not particularly heard many, though) and seen.
They make music, well, musical and can be considered audio phile grade in my opinion.
I am enjoying going back to music I have not listened to for a while as well as discovering new artists/genres. They play all genres well I feel.
They are very resolving but cohesive, the whole song is in harmony/makes sense. The Beyers are resolving, maybe more so in critical listening but the whole song sometimes does not 'quite' fit together on them.
The opening synthesised bass line of George Michael's 'White light' is electric on the X1's, it's 'weirdly-good' is the only way I can describe it
Well done Philips