three months later ...
... and Xcode 4.2 STILL can't build my Xcode 3.2.6 projects without MAJOR configuration fiddling, none of it documented by Apple. And after a couple of hours of Google'ing these obscure little tricks (like not using the new compiler just so the object files will link), while it might build, the simulator simply issues an "error 1" when I attempt to run it at which point I have no recourse other than to switch back to Xcode 3 if I want to pay the bills. I'm sure that Xcode 4.X is a wonderful thing for those people that it works for, but I'm also sure that there's a LOT of people for whom it doesn't work. Simply telling these people to shut up and get with the program is typical Apple-flavored arrogance. Instead, we should be telling Apple to make the thing work just as well as they say it does. When the thing will load my existing project and run it, then I'll be able to recommend to others that they switch over to it. Apple's policy of forcing people to switch to a new and buggy development system if they want to develop for Lion is just plain wrong, but typical ...