In terms of edge quality (not collectibility), would it be the case that some of the darker stones (blue/black) perform as well as the much sought yellow/green?

Blue/Black w/ Escher label vs yellow/green non-escher.

'Don't know how much heartburn to go through to chase the cherished Y/G.

Ideally, testing would be the way to decide, but from most private sellers, that's rarely possible.