I wouldn't consider the workstations sold by Xerox, TI, Connecting Machines, the OS research department at ETHZ or the Microsoft’s natural language search service for the West Coast and Asia, just experiments.
With a synchronous garbage collector for cycles. Which is like the worst of both worlds, since you get the constant overhead of refcounting, plus unpredictable interruptions of unspecified duration that can happen every time a new object that might contain references to other objects is created.
To be fair, the GC can be disabled. But it's only safe to do so when you know there are no cycles, and even when such guarantee can be had for your own code, I've never seen a library guarantee that to API clients.