A quick ride report with 33km/21mi of riding and 365m/1200ft of climbing. The chain rides pretty well. Shifting was accurate and the chain is fairly quiet. There's noticeably less drivetrain sound especially coming from my Goldix XDR cassette.
I'll have to ride it for longer distances to see if the chain holds up over time. At least for the short term report, these SUMC flattop chains seem decent.