My Cardboard app doesn't have stereoscopic effect on device. However it works in Editor.
This is how it looks in Editor. https://i.stack.imgur.com/sN14x.png
This is how it looks on device https://i.stack.imgur.com/7XpeD.png
It has worked with Unity 4.6.
I have tried it on multiple devices.
Config: -Unity 5.0.0f4 Personal -Cardboard SDK v0.4.5 -tried on Galaxy Note 4 and Nexus 10