So, that's two recommendations (with qualifications) for the high-contrast screens. I have never really looked at these. Since the main issue I've seen in high-ambient light conditions is the contrast (blacks), this might be well worth it. I'll have to look around and see if I can rent one in the area for one run, just to try it out before I buy.
Stewart Filmscreen used to have a demo at trade shows with a small 'room' with one half of the screen a standard matte finish and the other a high contrast surface of slightly lower gain. The high contrast screen had not only lower black levels but colors against a dark background appeared brighter. The downside was that white was not as white, so not necessarily as beneficial for viewing Word documents or Excel spreadsheets.