Is it?
Unity UI?
Really?
2 major versions and (at least) 4 years later?
When I first used Unity on version 2.6.1 they were already talking about it, everyone thought it would come in v3, nope…OK, v4 then? Nope.
Seems like it’ll be there on 5 (OK…4 and half plus a tenth), not too bad.
Well…
I know I’ll never finish a game, but I’m going to install the beta just to check it out. 
PS: I haven’t followed Unity for a while (haven’t installed any of the 4.x versions and only installed 3.0 and maybe the next two versions). But was looking at the Unity 5 features and selling points and it seems they – finally – went SpeedTree. Not that I will benefit from it (I finally accepted the reality that I don’t have the knowledge nor the talent needed to make a game). Also it seems to be subscription only at USD$19.99/month (why don’t they just round it to USD$20?)