Kevin Jones hits the nail on the head.  One of the biggest things we hear, as CustomerVision, is that when we provide people with a demonstration, we are not taking them through a powerpoint presentation and vaporware presentation, we are actually showing them the product, demonstrating capabilities and answering questions by showing how it would & can work in the client environment all within a 60 minute period of time. 

Kevin discusses on his blog, at Objection #14 - Prove it, the fact that people are quite skeptical these days about buying software and am "I" getting what "We" believe we're buying.  That's why client testimonials, references and demonstration are all critical and necessary for software vendors to prove their value.