Mark, CRs:
My 1996 Richard Sachs has the Ohtsuya lugset that you described as failure-prone on heavy-use bikes.
FWIW, I see no hints of this failure on my own bike. I am admittedly a lighter rider at about 160 pounds, but I did ride 6 centuries in the summer of 2005. My bike gets fairly consistent high-mileage use during the summer, with weekend rides of 80-100 miles duration each.
I'm not concerned about my own bike, but since nothing lasts forever, I've ordered another RS frameset "just in case" ;-) .
The skill of the builder is probably more critical on these small lugs than on bigger meat lugsets.
regards,
Andrew Gillis
Long Beach, CA