I got the international spec Galaxy S3 LTE a few days after the i5 came out, and a couple of my friends got the i5. Both have said the Samsung looks like a far better device so far. In my opinion, the S3 looks impressive and feels impressive - the iphone5 looks and feels just like the iphone 1, 2, 3 and 4 all did. Its boring.
Much has also been said about Apple Maps, but its difficult to understand just how bad they are until you stand on an island in the South China Sea and Google Maps is giving you a display with roads, towns, attractions etc on it, whilst the i5 presents literally a green blob on a blue background.
I've seen the S3 run 60mb+ on 4G with a speedtest app - there's not many countries in the world that have broadband speeds that fast. The range of what it can do is incredible, and im impressed by the battery life so far, given its power. I've had Endomondo tracking a 9 hour hike and the battery still had 40% left in it.