I found this article recently on Digital Tutors.  It has some good content in it about choosing your game engine. The article addresses the main free engines out there (all good quality), Unity, UDK and CryEngine. Many of these I have tested out myself during the course of the project. CryEngine and Unity are my favorites. Unity3D is the game engine platform of choice up at the Art Institute of Colorado.

http://blog.digitaltutors.com/unity-udk-cryengine-game-engine-choose/