Yeh I just read this earlier today too, great news!
I think we can much learn from the editor and get some inspiration for scene-worker , jgf etc.
Anyone got some unity3d-experiences already?
I've been using Unity for quite some time and it really is an exceptional product.
Particular strengths are the ease of bringing in assets, how everything is integrated into one editor.
You can set up a scene, your animations, make particle effects, configure physics etc. all from one GUI.
The community is excellent with a good forum like jME, and also events and a magazine (though it seems to be AWOL!).
Weaknesses funnily enough surround the coding aspect - you don't get source code so you can't see or change how things work. To get advanced effects and have access to the render pipeline you need Unity Pro.
Script editing is one thing that's not that well integrated and the editor is very basic. By the sounds of it, with 2.6 they have dramatically improved integration with Visual Studio - but I haven't tried that yet.
Other downsides are that while the editor is now available for Windows, you can only build to Mac or webplayer. There's no Linux support at all. The indie version displays a Unity splash screen/watermark in your app.
iPhone development is quality using exactly the same tools and languages. But you need one of the iPhone licenses for that, which you still have to pay for. And of course a Mac, and an Apple registered iPhone developer account.
All in all Unity lacks the flexibility you get with an open source engine, you can't code in Java, and the indie (now free) version lacks some important features. But it is an extremely robust and polished engine. It would be grossly over simplistic, but you could say Unity is strong where jME is weak, and vice-versa.
I'd recommend anybody working on jME tools give it a try if you haven't done so already.