About the default GUI looks I like AmigaOS4 the best.
(my MorphOS setup looks also nice after small tuning, slitaz looks nice, same for bodhi. but it seems if I tune Linux looks, I end up in situation where it malfunctions. Amigalike systems seem more robust for "tuning".)
So far there is not any "perfect" for me... so, customizable GUI is best for me.