Downloading now...its 1433 MB. Got it for my S4 yesterday and it was only around 950MB I think...seemed to run well on the S4, didn't really do too much testing though...
Finally, 4 months after I first installed stock Samsung Lollipop on my phone, AT&T are releasing THEIR OWN version of Lollipop, see #1.6 of 40 Galaxy S5 models - Dummies Guide.
This could be AT&T's chance to shine as they have now had enough time to release this on a much, much, higher changelist number than Verizon did with both their original Feb; OA8, and their recent OC4 release which were both based on their original, extremely old, changelist #3846539.
Changelog here:
EDIT: damn. The link broke.
Android 5.0 Lollipop Highlights
Songs, photos, apps, and even recent searches from one Android device can be immediately enjoyed across all of your Android devices.
New User Interface look and feel, more fluid motions
Priority mode to only allow certain notifications to get through
Battery saving features and remaining time left to charge or deplete indicators
Smart Lock to secure phone or tablet by pairing it with a trusted device like a wearable or car
Most frequently used settings available with just two swipes down from the top screen
Details at: http://www.android.com/versions/lollipop-5-0/