When people first learn a piece of software, they expect rival software to work exactly the same way or their brain instantly dismissed it. It happened to me when I switched from Windows to OSX, nothing was like how I expected and I had to change the whole way I use my OS, but in the end it was rewarding. Similar thing with GIMP: most people are weaned on photoshop so can't stand any workflow that is a bit different or not one-to-one feature-compatible. I learned GIMP first though so I never had any pains learning it and knew its limitations.