I have a heathkit exhaust analyzer. Still works for me, its good for when you have an old vehicle that has idling/emission issues to help you figure out lean/rich conditions. How much are they asking?
I'm into aircooled engines so if working, it would be a great addition to the arsenal of tools used to time cars and jet carburetors.
I have an Innova 5568 Pro timing light (that I want to be buried with, along with my TGR brake line flaring tool). An exhaust analyzer would give me a bit more information where the timing light left off, but they aren't cheap.