Why would you do this? Selling by slamming or degrading your competition only makes you look bad. The concept is to sell yourself, and your skills. Talk about your product and what you can do with it. When you attempt to degrade or slam a competitor, it is often seen as "I can't compete with them at their level, so I have to bring them down to my level". I just cant see any point in time where this story, or others like it, would ever be brought up to a client.