It's well performed with pristine production, but it's hard for me to say what audience this is really aimed for.  Obviously those into rock, pop or dance are not going to like the lack of a solid beat.  Those with more avant garde tastes will find this rather antiquated and stodgy.  Maybe this would appeal to the more conservative classical crowd, except that even masters like Beethoven, Bach and Mozart had a better ear for melodies that the masses would easily remember.  But one thing I do like is how the track Tithonos sounds uncannily like the soundtrack to Taxi Driver, although I'm not sure that's intentional.

Overall, this is rather pleasant baroque background music, if not especially memorable.  But more classically inclined people may find much to like from Green and Grey.