“The Violin Maker” by John Marchese explains how master craftsman Sam Zygmuntowicz competes with Stradivarius. Brooklyn based Zygmuntowicz strikes out against the notion that there is one great secret to these violins, but hundreds of small details that bring out their charm. In short, he can fool audiences on when a stradivarius and his own creations are used. But, world class players are able to differentiate between various violins. These players have personal preferences and can differentiate most violins. Its hard to say if his are better, but the value of his violins are growing faster.
NPR has a nice bit of some the methods Sam Zymunotowicz has used. http://www.npr.org/templates/story/story.php?storyId=96708334