There's a video on their Web site that shows what the display looks like in the glasses. It appears as if you're holding your iPod roughly a foot (30 cm) in front of your face.
Now, there is what looks like a cheaper unit that does something similar [link|http://www.firststreetonline.com/product.jsp?path=-1|7863&id=38106|here], but I still have similar concerns as with myvu.