We seem to highly regard DEMO over anything else.

"The majority seem to regard demo equipment more desirable than anything else, used. Could someone please tell me why?"

Its a safer purchase. There's all kinds of risk buying from private sellers. You're much less likely to have any problems when you use a dealer. Also, with a private seller, you have no idea how many times the component changed hands. If you've ever read some of the threads on this forum, you'll find that there's quite a few people who constantly buy used equipment to try it, and sell it a short time after. It may have changed hands 20 times, for all you know. Would you feel comfortable buying something that UPS/FedEx used for a soccer ball 20x? For a good description as to what I'm talking about, watch the beginning of Ace Ventura.

"I know there is a warranty but I have never had a piece break down in the first 2 years ."

Past performance is no guarantee of future results.

"With some brands that warranty is up to 20 years and is often only for the original purchaser."

Anyone can get the warranty. When a Bryston product is sold, it gets logged in the system, and that's all they go by. 50 people could own the amp and it doesn't matter. Less than 20 years and they fix it.