Never used one, though I interviewed at a place that bought a truckload of them about 5 years after IBM dropped the line. The company got them cheap and were trying to figure-out what to do with them. Seems that they got most of their hardware that way, didn't strike me as a good way to run an IT department.
By the way, the language that you're thinking of was EDL, Event Driven Language.
Keep Up with TechRepublic