I think Taiwanese build quality is very high. Obviously that's a generalisation, but to change the subject slightly, are Far Eastern cars less well built than US-built cars? I would say they're better. And the worst problems I have heard of in retro frames are with Fat Chance seat tubes and de Kerf stays. And maybe Crack'n'fails.
The big Taiwanese factories are efficient and well organised, and it's in the nature of things that they will use their very best welders to work on the best quality tubesets - welding a 7-4-7 tube to a head tube requires a greater degree of precision, delicacy and consistency than welding a 1.2mm plain gauge tube.
If we're going to say that the very best welders in a high-standards, well-organised Taiwanese factory are inferior to a US or Canadian welder, what are we actually saying? Are we racists? Where is our evidence?
I respect those Canadians who feel very strongly about this based on their patriotism, but we are not Canadians.
Having said all that, I have just bought an RM Equipe built in Vancouver, and my previous buy was a 1996 VooDoo Wanga, built in Chico CA - and that is the straightest frame with the best 15 year old paint I have yet seen.