I saw the Vutec at CEDIA. It was pretty interesting. If you put your hand in the light path, it really cast a nearly black shadow, even though it was in a very brightly lit area. They claimed a gain of 2.5. It had good horizontal spreading. I think most of the gain comes in the vertical direction. For normal viewing, the angle is probably good enough. Once you get to the extremes, it "shuts off" very quickly. The luminance vs angle function is more "square wave" than anything I've ever seen. Anyone have any idea how this works?
Also, there was a seam across the screen, even though the screen was pretty small (maybe 2' by 4').