I got into the beta. Not such a big fan. They showed the state machine as being very simple to use but when I had a look, I couldn't seem to figure it out (I did manage to make a sphere emit smoke though). The buttons, sliders, etc aren't that well labelled so I find that I have to just try everything to see what it does. Another thing is previewing. It's not such a big deal, but pressing Play doesn't automatically switch you to the main camera. You have to go to the top and choose the correct camera in the display list to view from there. Now that I think of it, that's actually pretty useful. You can easily switch between the OrbitCam and Main Camera while previewing the game. Also I'm not entirely sure if real time shadows work properly, or if I have no idea how to make them work.
I think I'll be sticking with Unity for 3D stuff