8
nothing of value changed really
Drag down alerts from incoming texts to reply without changing apps. Send audio text messages. Send locations. Gallery of all images transacted to a contact.
It's a bunch of little convenient things that make life so much easier. I've been using iOS 8 since it was announced (I'm an iOS developer so I get the beta) and these 'trivial' things very quickly become very useful.
The one feature that's
huge that I haven't yet gotten to try because I'm still on the last patch of the beta rather than the gold master release, third party keyboards. Swype functionality, complete redesigns, etc. Really opens up the keyboard platform.