These are quite interesting machines. It seems no-one can agree on their cleaning performance!
For what they are worth however (next to nothing), they can probably clean dishes, but just re-deposit all the garbage onto glasses and the like, being baked on during the Drying cycle. If anyone were to end up with the machine, you need to ensure it has a Rinse Agent (E.g. "Jet-Dry") dispenser, which could help cut back on rubbish collection.
It could also be beneficial to replace the pump in the machine (another debated subject), that may very well help things along, if the old sump has collected considerable amounts of garbage (which it will have) during its existence.
Whoever ends up with this machine will probably "enjoy" playing "Can you find the clean dish in the GE after the cycle is done?"
On a side note, I've just realised this machine uses the same upper rack as the one in the 1960's Mobile-Maid dishwashers. This means GE used that upper rack for the best part of 40 years! And the wash tower, through its various iterations...