Unity has been gaining a lot of traction especially because you write the game once and you can generate versions for a lot of platforms.
I haven't tried only the Android and MacOSX platforms so far. We developed a simple game that showcased the rift by journeying through the Mariannas Trench using the Oculus. It was quite remarkable running on MacOSX. WE had to do some simple mods to get it to run on the Android due to hardware limitations.
Here's a comparison article showing pros and cons that I found that may help you decide:
http://blog.digitaltutors.com/unity-udk-cryengine-game-engine-choose/