LARGE icons, with backgrounds, to make them all square.
Widgets - its like the iPhone with widgets, can you believe that!
Smoth scrolling, and themeable ROM, The rom itself is theme-able.
In other words, go to en.miui.com (this is the English version of the site), and see if your phone can run MIUI, if it can, GET IT NOW!
MIUI's smooth feel, easy to use UI is definatly the future of Android, not Android 5.0 "Jelly Bean" as many have started to call it.