I also have the Ref2 MK1 modified by GNSC. I am using Upscale Audio's EH 6992s which are a improvement over the stock ARC 6922s. I've never had the MKII in my system but do know another person that tried the MKII but preferred his MKI. However as Hjp states it also probably depends on one's personal preferences; at least to some extent.
