Promotional copy - any different in sound quality?

Sometimes, but not always, the promo copies come from earlier in the pressing run with an earlier stamper and earlier in the sequence off a given stamper. But there is no guarantee and no consistency about this. I won't pay a premium for a promo copy, but I'm always willing to give one a comparison listen just in case.

Yes, the promos are much better. I have spent enough time comparing the promo and non-promos of the same. The results are always the same. However, promo copies are often not in good condition.