mylar is very much a pain in the ass. white paint is a good choice, in my bud room one wall is painted flat white (its concrete block) and the other three are black and white plastic (sounds just like the panda film described in the above post but mine is not brand name or whatever). both work well for me, are easy to clean, and have been in a working budroom for over a year and i have not needed to repaint or repair any plastic film. i had tried mylar at first and it started to tear after just one cycle.... good luck dude, hope that helps!
kane