Those Darned Motivators
Have you ever submitted a proposal you knew was priced right and addressed the customer's need, but still lost the deal? Odds are there were personal motivators at work you didn't uncover.
Not all customers make buying decisions for "rational" reasons (price or specs). Many times factors such as comfort with the sales process, lack of trust in a new vendor, or simply resistance to change are just as important and can help you cinch the deal.
Don't just ask your customers "What's important to you about this product?", but ask them "What's going to be important to you in making this decision?" The answers might surprise you.