Been too busy between work and finishing drywall to spend much time comparing samples, but here's what I've got. I have small samples of BOC, some 1.0 gain material, and the other which is 1.3 gain. Because the samples were relatively small, it was hard to see too much difference in the materials. The first thing I did notice was that the 'grain' of the 1.0 material was noticeable to about 5 feet from the screen; about twice the distance where I seemed to loose the screen door effect. The grain of the other samples was lost much sooner. From a distance, there seemed to be a noticeable difference in the reflected light on the 1.3 material. Not surprisingly, it was brighter and the colors somewhat richer. Again, far from scientific, but the 1.3 gain material 'seemed' to perform better than both the BOC and the 1.0 material. It is a good bit more expensive, but still far cheaper than any purchased screen I can find. So, I am leaning toward the 1.3. I feel that I can build a really good screen with it for much cheaper than what I would spend to buy a pre-built.
I would love to hear what anyone else may have found.