Compare Sony Xperia Z and Samsung Galaxy S4?

I want to know that few days earlier Sony has launched it's new powerful gadget in the smartphone hub Sony Xperia Z in the market and reading it's specifications drive anyone crazy then why samsung galaxy S4 is considered much superior. Please make a comparison and share it.

This may be because Samsung has publicise more then Sony sets earlier. Though Sony Xperia Z is also very powerful and would make a nice comparable against Samsung Galaxy S4 but samung's galaxy series is now ruling the smartphone hub.