I've heard $1500. Just missed that era.
Remember though, the world was a different place back then. People were buying pins because they made them money, not because they were fun to have at home. If a machine earned money on route, there would be more of them sold. If a machine was super fun, but didn't earn, it didn't matter. It's different now.
Also, as to why a lot of people like to bash Stern, back in the day when they were playing in arcades, it was by FAR the most likely that they would come across Bally / Williams titles. All machines do feel different in some ways. That isn't a good thing or a bad thing, it's just true -- and so when those same people are going out looking for a pin to relive what they remember from the arcade, of course there is going to be nothing better than exactly what they remember.
Add to that B/W titles were relatively unreliable when you took them out of the box. DE was worse, Gottliebs were built like tanks. But, by the time that most collectors get them, these games have been tweaked, and tweaked, and tweaked, so opening up your new Stern game and finding out that a switch is out of alignment suddenly seems horrible. Machines were way worse back when B/W ruled the roost, but collectors don't see that side of it.
That's why people ultimately and unfairly bash Stern for what they have done over the past 12 or so years -- because they aren't exactly what they remember from 20 years ago, and they don't work as well right out of the box as a machine that a collector has spent hours and hours tweaking.
I like everything for completely different reasons. I don't currently own any Stern machines, but if an Iron Man came up for anything near a reasonable price, I'd be all over it. Heck, I haven't even played Tron, but from everything I've seen and read, it would be the same sort of situation. But, if I was looking to play games that played like they did back when I was a kid, those aren't going to be the machines that do it for me. Mostly, B/W titles will be. And, admittedly, I do own a lot of those titles.