I have owned the PCA-2.At the time ,in the context of my system,I found it to be very good sounding--but not special or exciting.The word that comes to mind is competent.
The user interface was outstanding;among the best I have used.At the time I opted to keep a Bel Canto Pre 1,a Sonic Frontiers Line 1 SE and a Consonance Cyber 222.I found them all to be more involving.
I currently own the PS Audio Trio P200 Preamplifier.Whilst the user interface is much simpler than the PCA-2,I find it to be sonically superior.It is as good or better than my other preamps,all of which retailed for a great deal more(Bel Canto Pre 2,Muse Model 3,and a Cary CPA 1).