i frequently recommend the HP when the user can't mount the projector close to the recommended height. People as a general rule buy low lumen output machines of the types we are discusssing and then want a huge screen and still light it very brightly. The solution is to get a high gain screen and to sit where or close to the maximum gain point. this is nothing new. Its done every day.
To evaluate a screen one has to see what a unioty gain reference quality screen does for an image You can't just put a bunch of samples up and say ya, i like the brightest one best and that's what almost everybody says. If you don't do, you know too much trouble to get samples etc, just rely on the manner who choose HP. There are a few screens with higher gain but even a blind man can see their inadequacy for 2D, particularly any high gain silver screen or the silver star made by Vutec.
If you look at HP, its looks ok. nice and bright. But you really can't judge irs negatives until you see what a screen that has no negatives, that is used by the studeos to edit etc looks like lit up. Then you can view the deterioration in image quality wrought by the HP. Of course you can say the brighter one is better. just like you can say a cheap speaker playing louder is bettter than an expensive speaker playing much more quietly. For the masses, being brighter simply overrides anything else.
i never ever thought going from a ref quality screen with a gain of 1.3 to one with a gain of 1.0 would significantly improve the image quality. Of course its a tad not as bright but I have a small screen, 4.5 x 8 ft, and a projector with more calibrated lumens out than those under discussion here.
My good friend, Professor Miller, wanted a very large screen and he wanted a bright image. Two very valid priorities. HP was the perfect choice for him. I wanted the absolutely best PQ I could get, one that if possible make the screen vanish and increase the level of realism. Something one has to experience in order to have a reference to base evaluations of lesser screens on. Few people have done this. They don't have black pit theaters and have projectors incapable of adequately lighting their large screen were it not for such screenhaving a large gain.
It is really nice to have a screen where there is image out to the limits of your peripheral vision like Professor Miller's screen. My HT does not permit a wider screen than much over 8 ft because of stairs on either side of the screen. So i din't have to choose width over absolute picture quality.
the only question I would ask HP owners is does your screen normally didsappear, not rarely or on ocassion. But always. If you are watching a sporting event, do you think your are there watching of course from a nice weather proof box and not sitting with the riff raff, just kidding, in the stands. you can give that up and trade it for big. I respect that choice but don't kid yourself what you are giving up because of that.