NDS Purchase

After a few years with my NDX I have upgraded to the NDS/555-DR.  I previously listened to the NDX/DAC combo but was never able to warm up to the sound.  The big 'aha' moment came when I did and A-B comparison between the NDX & NDS at my local dealer.  Having not listened to an NDS previously I did not know what to expect.  We listened to the NDX, then NDS, then NDX - at which time my reaction was 'where the heck did the music go'.  I literally could not believe how much of the music I was missing with the NDX (which BTW I really liked).  Having had the NDS running at home for a bit, I'd like to offer the following observations:

• Soundstage - the soundstage is very different from the NDX.  With the NDX, I was always aware of the L/R channels.  With the NDS this has completely gone away.  Each music component has it's location with a stunning presentation.    
• Everything is there - I feel for the first time that I am hearing all of the music.  The NDS accomplishes this in a very natural way and without causing listener fatigue.  
• Detail - with a vastly improved soundstage and a large increase in the music presented it could naturally lead to a loss of detail.  Not with the NDS.  Somehow the NDS also substantially increased detail.  Very nice!
• Bass - I was considering adding a sub to my set-up.  That is no longer necessary with the NDS - it really brings out the low end - while keeping an excellent overall tonal balance.
• Harshness - the NDS eliminated any harshness that was present with the NDX
• Black space - the NDS is very deep/quiet where it should be

My only down side so far is the 555-DR has a noticeable hum.