I can't speak for XS5, but since i do have WS55 i can speak for.
At first, it seems like it had a lot of sibilants when i turn up the music too high. This was caused by the headphone drivers being well made that it doesn't need volume up too high to get the full textured audio sound. Compare your old headphones with these babies at same volume level on your IPOD or computer. These headphones sound a little more closer radius than the M50 (but not by much), because of the way it was designed. I'm listening to a judas priest concert. I feel like i was there. It is an amazing headphone. Highs will sound rough or punchy (treble clefs hurts your ear if it's on too loud), however after a while, it evens out. Although i love this headphone, but it's really picky about music quality. If the quality sucks, then these headphones will tell you that they'll not like it by giving pain in your ear drums.