If you can afford the upgrade to a premium definitely do it. I am very happy I held out and ended up with a Premium machine in the long run.
Whatever the case, ACDC is simply a great machine and I have no doubt that thanks to ACDC, Stern would be in a very good place at the moment and can hopefully consistently increase the budget on future machines. It wouldn't surprise me at all if in 20-30 years ACDC is likened to Space Shuttle as being a machine that went a long way to guaranteeing pinball's future.