There's no bigger fan of that cover than I am (and I was salivating over Jon's Cole recreation of it), but I have to admit that a lot of Cole's "poster color" covers (Mask 1 and 2, Contact 12, Capt. Flight 11, etc.) need to be seen in person to get a full appreciation. Bright, flat copies look truly amazing.... and the colors are a big part of it. Cole used a lot of flat color without shading (a good example is Contact 12), and some people may consider them to be somewhat plain. However, I think that the simplicity is what makes it so eye-catching. When I pulled that Mask 1 out of the box, I imagined what it would look like on a newsstand. Put that up against other run-of-the-mill Fawcetts and DCs of the time period (1945) and tell me which one gets your attention!
I'm a real cover hound (as evident by my pre-code horror collecting habits and love of Jim Steranko's 60's Marvel covers) and this cover is possibly my all-time favorite. Even if I had to sell off big chunks of my (small) collection, I don't think I would ever part with this one.