Any advice on buying quality vinyl

I agree with the consensus. Clean, clean, clean.

I use an ultrasonic lab grade machine, running at 80KHz, in a 45C chemistry of lab grade detergent, followed by heroic rinsing in distilled water.

Yes, it's expensive, but the results can be quite spectacular - I would say at least as much as doubling the price of a major component. Added to that, the grunge that is removed (which includes diamond dust) is no longer grinding and reshaping your stylus, so in case of an expensive retip, the US setup is virtually free.

dynaquest writes "Scientists and audio engineers way smarter than you and I have trumped that notion."

Not scientists. Marketing types may say that, but it's not true. Some scientists can read a theorem and understand it.