Video of standard factory barrel versus custom barrel..
NO comparison on quality in what I feel is a very small price to pay considering the labor and quality involved..

Ripp

http://www.youtube.com/watch?v=hf9zZqn00CA

Additional info from various custom barrel manufacturers...Lilja and Hart --couple of the best..

http://www.hartbarrels.com/barrels.php

http://www.riflebarrels.com/about/default.htm