We've been using it as the prime development tool for our game for a few months now, it's very great in terms of ease of use and built in options as an editor.
It's been mildly annoying as an engine though, well in theory you can extend it in any way that mono/clr allows, it'd be nice to not have to. I planned to make a thread about some of my experiences when I'm closer to a fleshed out prototype. I'll re-iterate that I think it's a great tool for what it does,
One thing that's been a particular annoyance to me is the sound engine integration in unity, it uses some variation of FMOD that's stripped of a lot of core FMOD features, and all in all is really poorly documented.
One of the things I'm trying to do is make very heavy use of adaptive audio and music, something that's pretty easy to do in FMOD proper but so far seems fairly annoying in Unity.
I read the community forums and the consensus basically seemed to be, if you want that level of audio flexibility , you basically need to write your own system or do a lot of inelegant hacks to get them in there. I don't know about you guys, but we switched to unity to avoid having to do a lot of that.
Audio really is the only major weakness though IMHO, it just happens to be one very relevant to me.
Anyone have a really good resource for audio in unity? I'm hoping I'm just missing something and someone's already wrote a useful library before I roll up my sleeves.