My sincere thanks to all who responded. I've already got a NIB 6904, a pristine 6906, and as I said - am in the hunt for a 3913. Eventually, I'll buy one - it's not an either/or thing. Based on your input, I do believe I'll go ahead with purchasing this 3906 (I'm going back to the shop tomorrow). I'll post the pics when I get it.
Best regards,
Bill (XAVMECH)