They are great shifting and quiet running chains. Especially with Suntour New Winner freewheels. And I still have mine on my 79-80 sport tourer, and Vitus 979, and they perform fine. I remember an article testing chains in the 80s and the Sedisport won the Rockwell hardness test.
+1 on that. Just disassembled a '79 Trek running a Sedis chain that shifted effortlessly on the Suntour freewheel.
The bike is very original but I don't know how old the chain is. It is not worn and will be re-used when the bike goes back together.
For new builds I use KMC.