My review is based on this amplifier used with a Cocktail Audio X30 and a FiiO X5 playing 192/24 and 96/24 Studio Master FLAC files and not on CD's or analogue sources.
My headphones are Grado GS1000i's, Grado 80i's and Philips X1/00's
I have no other headphone amp to compare this too however I can say that there is a very definite and noticeable improvement when using this amplifier with my sources than just connection the headphones directly. The soundstage is wider and the points of each source, be it instrument or singer, seems more focused. I am happy with its performance and certainly think it is worth what I have paid.