New UI design & engine, content-aware and includes the new Camera RAW with adaptive wide angle, field blur & tilt-shift capability.

The download size is massive: 984 MB for [Mac](http://labsdownload.adobe.com/pub/labs/photoshopcs6/photoshopcs6_p1_mac_032112.dmg), and 1.7 GB for [Windows](http://labsdownload.adobe.com/pub/labs/photoshopcs6/photoshopcs6_p1_win_032112.zip). I’m curious as per why the Mac version is _only_ half the size of the Windows download.