UPDATE: Galaxy S4 (render) side by side comparison with Droid DNA & Galaxy S3 (including a more realistic Galaxy S4 mock-up)
Here it is:
By minimizing the bezel, Samsung could bump the screen size of Galaxy S3 up to 5 inches without increasing the overall size of the phone.. and with soft key buttons, it should be easier to hold & navigate compare to the two (DNA & Galaxy s3)..
UPDATE: A more realistic GALAXY S4 mock-up (middle):
Let's add another here, side by side with iPhone 5s! lol :)