The difference between blue and red is subtle, the blue is nearly black and the red is very dark. When my 4 year old used the colour changer she pushed really hard because she couldn't really tell if the colours had changed or not (I threw it in the garbage before she damaged the drawing area). It also erases very slowly, it takes 2 or 3 slow pulls of the eraser to completely erase the drawing.
I got this for my brother for Christmas last year. He used it for MAYBE a month before switching back to his black-and-white one. The colored shavings don't magnify as well as the untinted ones, and the colors are not NEARLY as bright as they want you to think they are. It also doesn't come with any of the cool stamps my brother likes.