The worst Amiga has to be the A600.
I think the A500+ is passable because it advanced the A500's architecture and brought us ECS and Workbench 2.x to the low end systems, but the A600 was just a plain step backwards. If the A1200 came along straight away instead of the A600 (a good 6 months earlier or so) things would have been so much better, and they would have been another 5-6 months ahead with AAA by the time Commodore folded (or completed it for all I know)
