Bob,
Thanks for your thorough--and very insightful--response. I completely agree with you about keeping components until, a) you are sure they are fully broken in, and b) you have done your best to find the right cables, meaning ALL cables, including speaker cables, interconnects, and power cords. Of course, this is problematic for many of us, particularly if we are auditioning a component under a fairly brief time limit. However, I think you are spot on in your observation that many people may give up on a component before they have heard what it can really do, under the right circumstances, when that elusive "synergy" is finally realized.
I'm glad the Marantz is working for you now. I hope to hear one someday.