I'm not a professional photographer, but if I edit shots, I use GIMP. This is only because it's cheap and I'm cheap too, so things work out. However, it seems like the overwhelming majority of people use Photoshop, and some use Aperture. Because of this, I started wondering why more people aren't using GIMP. Is it because of a lack of features or support, or because it's a hassle to switch programs? How far does GIMP have to go before it's a real alternative to Photoshop for Pro users?