Re: GIMP may be powerful...
I have to agree. Like Blender and others, the interface can be painful to the "uninformed user". It is far from intuitive and will likely lead to repeated head scratching, unless you use it regularly.
Furthermore, the usage of the "language" Scheme for Script-Fu script plugins is a wicked choice. I'm quite sure that Scheme wasn't intended as a real programming language, but rather as a joke – very much like Brainfuck. ;-)