Today I used a vintage Schick Deluxe with Krona Edge, a coated carbon-steel DE blade that was probably a competitor to the Gillette Super Blue blade.
It started out nicely, a little first-pass tugging (typical of old carbons) but cutting well on my heavy stubble. Great second pass, but I could feel it losing its legs toward the end. Lots of buffing in pass 3 since the sharpness was pretty much gone. A good job overall, but it's in the bin after one outing. I only had one blade in the dispenser, so I'll never know if it was just a fluke.