Just downloaded 7.0.3 on my iP4.
+ Animations are a lot faster. I did a test of unlocking the phone, going into Music.app and skipping an already playing song, and I think it's about ⅓ faster at least, since the icons don't need to fly in and the app doesn't need to zoom up.
+ Spotlight pulldown is now smooth(er), and you can search Wikipedia or the internet from there again (it was sorely missed by me, since launching Safari pre-7.0.3 was slow as hell)
+ I tested the response time of a rather slow loading app, Agenda Calendar 4, and from cold launch, it would before become responsive after 11 seconds. This has now been reduced to 8, and the animations in the app is much smoother.
+ The lock screen camera shortcut now always registers my finger.
+ Keyboard seems snappier and more responsive in almost all apps.