Never heard the ARC, but another strong vote for the K&K. I too have used a number of units:
Tom Evans Microgroove
Audio Synthesis Passion
I have heard numerous others, the Whest, Tom Evans Groove, Bel Canto, Chord Reference and none came close to the K&K. Its detailed but fatigue free, a rich sound excellent soundstage, but above all QUIET, I never really realised how important this was till hearing this stage. A final plus, it is the only stage I have ever used that does'nt pick up stray radio stations.
Are there better stages out there? I am sure there are and you will hear many people berate transformer as against active MC gain, but the Lundahl transformers in the K&K seem fine to me. I see no prospect of changing my unit and I can't say that about many other components.
One thought, go on the Audioasylum special K&K site and see if there is a user of the unit near to you who might audition it. I am in the UK, not very practical.