My recollection of the Echoplex was when we (the supper club trio I was in as a sideman) encountered a friend of the band leader playing solo guitar in the lobby of a hotel in the town we were playing that week. He was using an Echoplex. As I recall, he told us that the hotel had to pay sideman's wage for the Echoplex as per the union rules. We were all (the hundreds of bands like ours that were touring at the time) AF of M union back then in order to play Holiday Inns and supper clubs.
Anyway, I as impressed with the guy's Echoplex. I never owned one (couldn't afford it back then), but I do have a Gibson Echoplex Digital Pro Plus with the foot pedal in mint condition:
http://www.loopers-delight.com/tools.../echoplex.html
Mine is exactly like the one on top on that page, the black one. I also have two of the earlier Oberheim units. These are nothing like the original Echoplex, but they are really nice in their own right.
Tony