Alexander Birke
I have been using Unity for 3 different adventure games now and it works really well. For The Adventurers of Bertram Fiddle, the game I am working on now, we are using the new 2D sprite system and it works really well. The 2D physics system has some bugs though, which means we have had to also use the 3D physics system in some cases. A nice aspect of Unity is that is it very easy to write your own extensions to the engine so you for example can have a custom timeline or sequencer which has enabled the animator on our team to set up puzzles on his own without having to script anything. We have a dev blog were all this is covered in greater detail:

I wish I had known about Adventure Creator before we started out though, that could probably have helped us save a lot of time.