Hegel comparison

Both are great amps.  I've spent quite a bit of time with both and also the new 600.  The 590 will drive the bass harder and tighter but the 590 has a small dip in the midrange which makes the 390 sound "warmer" side by side.  I think it's the DAC in the 590 that causes the midrange dip.  I used an external DAC on the 590 and the dip vanished.  Good luck and cheers.  

They do sound a little different. I believe the 390 is a touch cooler sounding. 
the 590 is a big deal because it has true balance and an extra XLR input. Plus since they just came out with the 600 you should get a better discount percentage on the 590. Most people are working their way up the line from the 95 up. So why not just get the best. If you are near Chicago you can go to Holm Audio. You might want to call for prices anyways. They will ship it to you and have a great relationship with Hegel. I hope this helps. 

I really think the question is new or used?  From what I understand the 590 is reduced to around $8K since the release of the 600.  Close to the same as the 390 new.  Used the 390 is in the low $4K range, dipping into high $3K recently, the 590 in the mid-high $5K range.  I have both and bought both used.  Some say night and day, others and I hear subtle differences, leaning to the 590.  I have heard a few who prefer the 390.  Strongly suspect if I plugged the 390 back in I would forget the differences in a few days.

US Audio Mart has a 590 rated excellant for $5500. I would not hesitate to buy a Hegel amp used.  IMHO

The dacs inside the Hegels are a comprised version of their standalone dac. I had multiple top of the line Hegel integrated amps in the past and never used their internal dacs. I actually had Hegel at an audio show compare the difference between the internal dac and their standalone and they were miles apart in sq. But very nice integrated amps.