This is an excellent work. It works really well usually however with 1.4.5 it freezes a bit when loading up my zen. I have the rare plain zen. no plus or micro or photo. It is a zen 20gb which was available fro about a minute in singapore, us and online! If XNJB freezes you haveto reset your zen, not a big problem just a bit annoying. 1.4.4 was fine however! I have reinstalled my iBook and still the same issues. Hopefully 1.4.6 won't have this problem. I have used this from 1.3.5 and this is the first time this has happened. When sync is implemented and fixes have been added then this will be the best on mac and pc! mediasource and windows media player for zens are big and slow. Zen media explorer, the windows explorer add in is just that an add-in, it confilcts with some removable media. The only thing they have over xnjb is the tag editing.