What a surprise. Fraisa putting the BD screen into another thread....
You forgot to mention those shots were done with ambient light directly hitting the screen, which obviously favor the BD screen.
However, for someone who wants to be able to watch their projected image with some lights on there are various ways of going about achieving that goal. If you don't want to invest any energy in intelligently setting up your room, you can instead invest more of your money in a specialty screen like the Black Diamond, which does some of your work for you. Although at some price...in terms of hotspotting, screen texture, and in the case of the .8 gain version, generally being relegated to small screen sizes due to the low gain effect on image brightness.
Another way of skinning that cat is just paying attention to how you set up your room and system. Keep your screen area darker than the area you want lit up, which is typically were you are sitting. No screen looks better with light shining directly on it, whether you are talking a Black Diamond or a white screen, so light shining over or on the screen isn't something you want in the first place.
My lighting is set in zones so I simply have the lights off over the screen, but lights toward the middle of the room back to the sitting area can remain on, with an extremely vivid image left on the projection screen. (Frankly, more vivid than I've seen with the BD screen in ambient light).
I have yet to take screen shots with an eye to showing actual image quality. I just snapped a few for my build thread showing different screen sizes. But I left the lights on in the room, except over the screen, and you can see what I mean about how the image still looks clear and rich, with good contrast:
