Source: www.xboxinsider.net
Written by Tamizander
I always, always try to play the demo of a game that I’m considering buying. I wait. I check Xbox Marketplace. Generally, I enjoy the game and rent/buy it to give myself more time to play it. Sometimes, I’m disappointed and I pass on the game. Nowadays, demos before release are getting rarer and rarer. In a world where we’ve gotten used to trying the game before we buy it (XBL Arcade, anyone?), it’s not as much our disappointment with being unable to play a game, but what not having a demo before release has become to mean to gamers. But, is there any correlation between a demo before release and after release? Does it change the game’s quality, or does it affect sales? Let’s dig deeper.
It's an interesting read and the author also qouted vgchartz. 
To read the whole article just click the link.
http://www.xboxinsider.net/to-demo-or-not-to-demo-does-it-matter/
