1) "UI by programmers". Very low use of graphics and animations. Everything looks very standardized. Usually has advanced options panels that let you tweak small parts of the algorithm. Gives a high level of control as there is little abstraction between the functional and presentation layers.

2) "UI by designers". Use of graphics and animations where necessary to make the UI more understandable, such as animations to show the result of user actions. Code is usually abstracted away and the interface is set up with the user in mind. Steps to perform common actions are very quick with the minimal amount of user input.

3) "UI by artists". Excessive use of graphics and animations. Animations that serve no functional purpose. High use of art with large images used for theme rather than function. Often no real link between what you expect buttons to do and what they really do. Steps to perform common actions are usually convoluted with multiple menus. Some even use hidden menus that must be invoked through arcane gestures in an effort to make screenshots look more appealing.

I think the UI being described here is actually the "UI by artists" rather than a well designed UI by a designer and not an artist.