> pretty

I'd have comments on other points as well but if there is one thing KDE apps generally aren't then they consistently aren't pretty. I know, eye of beholder, but it's almost as bad as TK. In the link you provided there are:

- grooved borders between every second UI element.

- icons are way too colorful with gradients everywhere.

- underscore hints on menus are ugly.

- places panel takes up way too much space and eats away at the tree view panel.

That said, I use Dolphin, but only because other file browsers on Linux are for various reasons bigger catastrophes.