Open-back headphones are a bit of an acquired taste. By allowing the sound to escape from the back of the 'phone rather than be 'fired' direct into the ear you get a literally more 'open' flavour.
It's a surprising experience akin to mounting high quality monitors on your shoulders. Of course, this renders open backs as useless for recording or 'on the bus' music listening duties as leakage levels are off the scale.
However, for in-depth precision listening during the mix stage we found the 1840s incredibly useful. Rather than simply 'checking on headphones' we were able to accurately locate and adjust mix queries that our monitors kept masked.
The 1840s' perspective is super-true with a widescreen look at your music in detail that you simply wouldn't think possible with headphones.
Brilliantly precise monitoring experience.
You won't want to wear them in public.
Highly recommended for those who require mix accuracy but must keep levels low.