I have been using Unity 3D for the last three days, it's just amazing. Really. Much easier than Torque, and I don't even want to say how gamestudio compares to it. Maybe because I still am pretty fond of A6/7. With the Mac and now Wii compatibility in addition to Windows and web browser playability, tidy Javascript, flexible resuable template style objects which work well, I think I might move my game to Unity 3D.

The terrain system and world editor and stunning, and you can just plop assets into the scene without complex conversions first, like my player fbx has been a nightmare to convert to MDL in MED, with repeated attempts and lots of time out the window. But in Unity, just drop the sucker into the level as fbx or blender or maya format, and it automatically takes care of the rest.

I think it's worth a Macintosh (or Hackintosh)