I'd give them a 4 out of 5, the sound is excellent, but once you get the bass way up they start to vibrate quite noticeably.
They are super comfortable though and would highly recommend.
My Shure E2c's are better, but not good for extended listening
You may want to note 555's are open type so noise will leak out - may not be an issue, but you have the benefit (or drawback) of being able to hear stuff going on around you.
(A bomb could go off with my E2c's & i'd be oblivious)