If you're cooking over gas, flat doesn't matter that much. I'm cooking on a glass top, so it does. All clad is a local manufacturer here, so that is what we buy in general. It's also the only pans I've ever had where you can be downright abusive and they won't go out of flat (and they heat evenly). There is probably a decent three layer clad knockoff by now - not sure.
They are a pan that I will buy used, too, if found in decent shape on ebay because they don't warp. I've often poured water in them in a rush while still hot to expedite later cleaning, or accidentally left them on a burner hot.
The only complaint I've ever heard about them other than price is that they can be a bit heavy (like cast iron is, too) for ladies who have slight wrist strength.
In diners here, I've noticed the ones where the principal owner is working the grill still, he will generally have a pan or two that have pretty much never been cleaned, and each time they have an egg order, they'll use that seasoned filthy pan. I lobbied for that but as filthy of a person as I am, my mrs. keeps the upstairs immaculate, and I could never get away with such a thing.
Old cast is the only cast to have if food will come in direct contact with it. Lodge still makes cast here, but the grain is so coarse that it gets food gripping small voids between them and you can't season that out of them. Wagner and another one were local here (Pittsburgh - i believe the pans were generally made in erie two hours north) .....I can't remember the second brand name, but they are pearls (some have an intentionally domed bottom, though, which doesn't work on my glass top).
