I agree, people get all caught up on the screens are this magic thing. Years ago when projectors did not have as good of contrast ratings, a screen with a slight gray tint helped somewhat, but as arcticair mentioned, you will sacrifice in other areas. On the opposite side is having a high power screen will give you more pop to the image, however, black levels can suffer. A "matte white" screen is the middle of the road with a 1.0 lumen gain. It has been around for ever.
I played around with paint methods for a long time. ME (misty evening), ME+, SM/MMud, silverscreen, and good ole Black Out cloth. They all had pros and cons. In the end I just built a frame and stretched some Dazian PVC matte white non-perf material around and attached with velcro. The picture is great.
I also painted my back wall flat black and the side walls/ceiling a dark blue.
