What's been consistently mentioned is that the sound quality of this player is the best. The issue I suppose is whether the sound quality is good, or whether merely the flavour is more adjustable. If the quality isn't as good, then the adjustability doesn't make it any better. For sound quality considerations, I don't consider the EQ as a component of that, although obviously it's an important part of adjusting what you want out of the sound.
As far as the adjustability is concerned, it is easily the most comprehensive of any player I've seen.
I do like the usability of the player, combined with some features which are nice to have. Although the HD3 will see considerably less use primarily because I find it an absolute PITA for general operation, it is worrying to note at this point that even the HD3 seemed to edge ahead of the Karma by a whisker in certain aspects of core sound quality. I haven't paid too much attention yet, will do more tests later.
Apart from the fact that I was curious and the price was low, I had a definite use for this player based the claims of superior sound quality (and other people who probably read yours) and also the adjustability. I'll definitely keep you posted on what I think.