I am not exactly fan of the AK signature, but I am open to giving the SP2000 a listen. The SP1000M sounded nice, but was somewhat sterile, can't put my finger on what it was exactly, it's been a while. The DMP-Z1 to my ears, is magic in a box, if they can replicate some of that for the next Walkman DAP, that will be a day 1 purchase. The DMP is stupidly expensive, but Sony put their money where their mouth is with the quality of build and Sound. Also looking forward to hearing what you have to say about the IER-Z1R.