@Tiles: The important thing is that YOU can work with Caligari's GUI. If you feel comfortable with... it's ok. The only thing i dont like are the too colorful buttons. I like Lightwave's grey-style much more.

But there is one important thing you have to keep in mind: The features and the costs. If you have only a small amount of "available" applications, the UI moves more and more to the background.

Example: A user has not enough money to buy 3ds max, maya, lightwave and so on. trueSpace and Blender are free. He likes Caligari's UI much more but he needs the import/export-capabilities of Blender. What's his choice?

What i want to say is: The UI is not a important aspect. It's only a question of learning.