I already use an MZ-NHF800 as my primary music player (sorry iPopd!) with ONE computer in nine that runs windose just for the sole purpose of Sonicstage software that converts WAV/MP3 to ATRAC the native NetMD/Hi-MD format.
Also here! SonicStage is windows only :-((((
Do you use it only for data on Amiga? As far i know it is not possible to record atrac on the MD without Sonic Stage.