I've compared my JR 625 S2 amplifier to several other amplifiers in my system and I prefer the 625 S2. I haven't compared the Corus to any other preamp; therefore I don't know, what I don't know. Unless I compare the Corus to other similarly priced preamps, I simply don't know the strengths or weaknesses it has. For what it's worth, many people have told me the Corus is my weak link and now I'm curious to hear other preamps.
As far as you not liking Rowland...there are no absolutes in audio, only preferences.