Iphone 4 to 5s, what's the perks?

Ever since i upgraded to the new ios7 my iphone 4 is just ridiculously slow. So i was thinking of upgrading to the 5s now, what are the biggest perks? I know it will have imessage, apps, same deal right? Only faster? And a better camera?

I do definitely like the idea of a better camera. And faster is always nicer, but is that it?

We'll its bigger (definitely) it's more HD with the picture. They've added more pixels to the cam, but I'm not sure if zooming in is better! Basically how HD the picture is