The word high is often associated with something good or better than low. High gain screens mean higher reflectivity which also means a brighter image. The home theater environment however, poses certain exceptions to the usual perception.
A high gain screen can put limitations on the number of optimum viewing seats which can be had on a home theater. It also does not typically reflect red, green and blue equally which can generate color shifts in the image that are more noticeable as the viewer moves around the screen from different angles. Screens with a gain higher than 1.0, would inevitably have some degree of hot-spotting, which is essentially the brighter appearance of the middle portion of the image than the edges. Gain screens higher than 1.3 can be very distracting. They are in their best elements in conference rooms and classrooms.