I first considered the portability of styrofoam, then thought, where was I going to put the stuff out of the way, and besides, would I ever take it down? I was fortunate to have a long wall that I could dedicate to a design wall. I've never regretted it, and more so, wonder how I ever did anything without it. It often holds more than one project .... and even a solo block from some of my PhDs as a reminder to return to them!
I used 4'x8' tentest boards wrapped with black polar fleece, held in place with the staple gun on the backside. Then screwed the boards onto the wall side by side.