blender is a great example of how poor people can be at UI design. why open source usually very shitty UI?? it's unfortunate, and is the major reason i stay away from linux (that and font rendering, which is related)
I'm not going to disagree about Blender's interface; I don't like it much, either. But I am used to other 3D programs, so perhaps I am not the best judge.
UI is a tricky thing, especially in graphics applications, where once you're used to one application, the others feel wrong. And especially in 3D applications, where there's no standardization -- look at Max and Maya, both now from the same company, or look at ZBrush, whose interface is equal parts brilliance and lunacy (although version 3 is much improved).
This is not merely an open-source vs. proprietary thing; Blender's interface was at least as bad when it was a proprietary product. Wings3D, on the other hand, has one of my favorite interfaces. It's open source, but its interface is inspired by Nendo, a defunct commercial product.
