Which is the classic mistake, "Selling features instead of benefits" or "Selling features when you should be selling benefits?" Honestly, trying to sum it up with only the two words "feature" and "benefit" is an enormous mistake as well.
Feature: My software uses closures. (Who cares?)
Benefit: My software will save you tons of money. (Bullshit, show me how.)
In "The Art of Project Management" (http://books.google.com/books?id=q1dJZv4Ycr8C&dq=the+art...), Scott Berkun insists that a good PM write feature statements as they directly face the customer. "My software will save you tons of money" is a fine benefit statement, but the feature statement shouldn't be "My software uses closures" but rather "The order entry system will consist of a single screen." Perhaps this is because of some technical feat that only you can appreciate, but the feature statement wouldn't ever mention closures.
Feature: My software uses closures. (Who cares?)
Benefit: My software will save you tons of money. (Bullshit, show me how.)