Was quite impressed by these sample videos, so I bought one to put on my quads. 50Euro including taxes is not much for a 4K action cam, would cost at least 30E more if I'd buy one in my own country.
Was thinking about buying a GoPro Session, but I read those Sessions are quite fragile, so I decided it was too expensive considering the risk of breaking it on the first crash. This iMars is a real good alternative, cheap and pretty close to the GoPro imagequality.