One of the things that Microsoft touts in their Windows 10 OS is the ability to stream the Xbox One to the PC. It's a pretty cool feature, but you're limited to a Windows 10 machine to stream to. Sony's taking a little different approach.
The next update for the PlayStation 4 will allow you to remote play on any PC or Mac so you won't be limited by operating system. It's something you can do now with a mobile phone as I've used the Remote Play on my Note 4, but it's good to see the PC and the Mac getting the ability to do so as well.
There are other new features such as new social updates and the ability to stream to DailyMotion, but the Remote Play to PC and Mac is the big one here. You won't be able to test it during the beta, but it will be out once the update is released to the masses.