That site looks pretty awful to me, while I can clearly make out the buttons from other elements it looks like a old stock Drupal theme or something along those lines.
Design is highly subjective, but from the designer's eye, there is no comparison between the two sites.
I am pretty sure core to "Flat UI" is that drop shadows shouldn't be used, and there is hardly an element on that site that isn't full of them.
Flat UI is not "flat", please read up on the topic.