I agree with Dan, they believe in form more than function. Personally, i used linux and open source stuff for years, and still use some of it. but i can't stand an ugly interface... like at all. if something doesn't look good then i just can't work with it.
Here's an example, I used Gimp and photoshop to do the same thing, the result looked better in photoshop even though i took the exact same steps. why? because, even thought the technical part of it was identical, the artistic part was flawed in GIMP because of the distracting interface and terrible design and workflow.
I don't understand why they can't just get a team of designers to help them or at least google design principles if they can't afford a team, they need it desperately!
one exception though is Blender, which makes its $5000 counterpart (Maya) look disgusting.