I got one of T-Visor.com's newer darker visors, and its just as dark as the BM (I have a BM too). The problem I think is that it just appears lighter because its a different color. The BM is a purplish tint, and the T-Visor.com is smoke... I think it may trick the eye, but when its in the helmet, theres not much difference at all (if any).
The BM has a nicer cut and curve, but its slightly spotty in some places. The T-Visor.com is crystal clear, but seems to have a wide curve and will need some trimming to fit properly. Could be the helmet that I'm using it in though.
To be honest, I think that one is just as good as the other when you weigh the pros and cons of each. They are both very nice visors, you can't go wrong with either one.
-Shawn