The viewer is assembled within seconds. Everything fits together great. The lenses seem unfortunately to be made of plastic. At the very least suggests that the sound.
The Cardboard software from Google a lot of fun and it's really remarkable what you can do with some cardboard. As smartphone came with me a Galaxy Nexus to use. The magnetic switch works mostly good.
To come to terms with the matter of virtual reality and play a couple of examples to look at or is this just the right viewer.
However, a disadvantage is the board itself. You sweat in summer or has a slightly oily skin, so the end leaves a footprint on the board that does not limit the function, but looks very ugly and disgusting is safe for some people.
A substitute for Oculus Rift, it is not natural!