I had opportunity to play with V1 in 1999.
I was working as a consultant for an Architectural firm here in Sweden that had been using ArchiCAD since V3, Graphisoft was here to do an story on them.
It was really quite impressive, Plotmaker was non existent. When I had a play with it I was running it on beige G3 which was running MAC OS 7 point something, surprisingly it run quiet well.
Cheers.
Ben