The HD700 cries out for a gray surfaced screen. I was especially pleased with how well it paired with my Firehawk G3 (128" diagonal), which is a high contrast gray screen. By comparison, I wasn't nearly as satisfied watching in the testing room on a 1.4 gain Carada Brilliant White (106" diagonal). With that screen the image was really bright, but black levels, weren't very! Letterboxes were a rather noticeable medium dark gray it seemed.
I'm sure some of you, who are less concerned about dark black levels could be happy pairing the Cinetron projector with a bright white surface screen, especially in a situation where maximum brightness is essential. (Like a 160 inch screen!)