Mac is very confusing so you'll find my vote is Windows. I've used a Mac, but it didn't make much sense. It's a good thing I only use it in my one class and rarely even then. Not including the slow operating systems in Windows (for example Windows Vista)
Well I guess I'll just comment on the picture itself. Aside from the idea, which is wonderfully neutral, the composition is very impressive. The usage of the logos to solely create the picture is really clever to me. On top of that, the black and white makes the blue and red logos really stand out (which I'm sure was the idea).
Well, that wasn't very eloquent, but I think you get the idea. Great job! This must've taken a lot of patience to get just right. I tip my hat to you, sir.