The "Auto-Ten" [I think the model number was 661... but its been a while and I could be mistaken] was mainly thought of as an expander... and like all the stuff in the Fairchild "solid state" series -- pretty much sucked as a tool but could be an interesting effect if "stellar audio" wasn't your end goal.
The Kepex was a definite and vast improvement, but it was indeed not the first dynamics unit of that nature. Many Kepex's were replaced by Roger Meyer [Mayer?] gates that fit in the same frame which were a bit more flexible in their use, and arguably, a bit more "audiophile".
In my twisted little world, when I first ran into the Drawmer DS-201, that was the game changer that had me using gates way more often [and frankly, probably more than I should have... but it seemed like a good idea at the time].
Peace