Haven't heard all those amps, but I am an owner of the Ref 2 Mk I for 5 years and bought it used. Never had a problem. I have been auditioning the Ref 3 and will probably purchase that soon. However, the difference is subtle. In comparison, I recently replaced the PHSE3 phono with the PH 5. WOW. And I more recently replaced the CD 3 MKII (upgraded) with the CD 7. WOW, WOW. Point being that if you go for the Ref II MK I, while it is not as coherent or musical as the Ref 3, (now considered by many to be amongst the 3 or 4 best line stages regardless of price) you will not be disappointed. Go for it.
The best sounding Audio Research Line Stage preamp
I'm in the market for a used Audio Research Line Stage preamp and was wondering if anybody with experience on the following models could help me as to which you might feel would be the best sounding model. I'm after the ARC brand due to it's noted dynamics and clarity. It will be hooked up to a Classe CA-301 power amp and a pair of Magnepan's 3.6R speakers. These are the models I'm considering. The LS2B MkII, LS3B, LS5 MkII, LS12, LS16 MkII, LS22, and the LS25MkII. Thank you for all your help.