The lens coatings in the simplest terms reduce light reflections and allow for greater light transmission. An uncoated lens surface will reflect about 4% per air to glass surface. In a typical riflescope there are 12 air to glass surfaces if you include the erector lens inside the scope. These surfaces also will reduce light transmisson. The light transmisson directly relates to the quality of glass and quality and quanity of coatings. Some companies try to improve low quality glass by applying excessive coatings. My choice is Zeiss as they first devoloped lens coatings in 1930. I feel that you can't argue with that kind of experience. Just look through of their scopes. Also, they use at least seven coatings per air to glass suface. When it comes to price on optics you get exactly what you pay for.