I own both and no doubt that the XP-20 is better, much better.Is by far the quietest preamp i ever hear.
Better and bigger soudstage, a lot of detail, better and powerfull bass.
The XP-20 needs mínimum 5 days of warm up to bring you the full potential and if you can, upgrade the umbilical powercord with a Revelation Audio Labs Cryo Silver Reference DB-25.....the results are outstanding!!!!
Cheers
Pablo