CryEngine 3 is in a unstable state at the moment. Adding textures to the game causes crashes and their importing and building the .exe is bad. Unity3D is best to use ATM. You will only be able to make cool maps in CryEngine which i guess is good but everything in the engine is made by them and you don't have 100% control over your game they do :/ some friendly advice.
im likin the cryenginge but as obrozz said, unity has alot more options and cry likes to crash alot....