Seth Godin has some interesting thoughts on product prototypes in a recent blog entry:
"Too many times, I've gotten excited about an idea and created a conceptual prototype. And almost every time, people, smart people, didn't get it.It seems counter-intuitive (or at least in some sense deceptive) to make your prototype better than your finished product, especially if you're a person who likes to set expectations low and over-deliver. But Godin may be onto something.
Here's my new prototype rule of thumb: your prototype has to be better (better build quality, faster interface, better lighting, whatever) than the finished product is going to be. That's what people expect anyway--they see your prototype and take off 20% for reality."