I went to all 4 SuperAuctions in so cal this past year. One of them was a complete waste of time. The other 3, especially the one last month was pretty damn good.
I bought a dedicated MK for $65, dedicated MK2 for $265, and a SVC Chaos in a Capcom big blue that had been painted black for $110. These all worked. The MK power supply went out, so had to replace, but that's it. These prices are after tax and auction fees.
A Simpsons 4 player went for $100, working. Aerosmith went for $100. I wish I had brought a bigger truck.
The pinball selection sucked though. Only the first 2 auctions early last year had any pins worth mentioning.