I've literally completed the flash less than 5 minutes ago, and rushed through the interface to see what's new.
Yes, the rumours were true - this update brings the nifty Camera app known already from the Z1 to it's predecessor. So now Z owners can take pictures directly to Evernote. Or to any other app, that support camera integration. Great idea, I'm hoping to see that back on stock Android one day. I was hoping to find the InfoEye location and object-recognizing and QR scanner camear app from the Z1 here. But it's not there. I'm keeping my fingers crossed for getting this when the update starts to roll out over the air.
Xperia Home basically hasn't changed. And I'm not expecting an update here either from the upcoming 4.4 update. After all, Google seems to have taken a good look at Xperia Home and used some good ideas in the new stock Home.
The Launcher has gotten a nice update though. A bit of inspiration from Stock Android, and a bit if inspiration from iOS (I hate admitting that as much as the next Android lover). Scrolling through apps is still the same, but swiping from the left edge now opens up a menu with quick access to Search, Uninstall, filter and sort by Most used, Own order, Installed and Alphabetical. Google's Play Store and Sony's own Sony Select are also accessible through here.
Apart from all of this, the update seems to bring a new font and a bunch of friendly smooth animations to the interface. My first impression is also that it's a bit faster, but that's based on very little testing so far.