I'm getting an AmigaONE almost entirely because I *love* developing for AmigaOS, and don't really enjoy developing for Windows or Linux. OS4 takes the platform I love and extends and improves on it, so i can't wait.
Also, sheer bloody minded stubborness is a factor. I saved up for a Phase 5 G4 card, then an AmiJoe, and now an AmigaONE. One way or another i'm damn well going to get a G4 powered AmigaOS box if it kills me :-D i've waited long enough...
