There is a good article on Gamasutra about the merits and precautions of early consumer testing from the experiences of NetDevil. More developers are using Scrum and have builds that show value very early in development. This creates an opportunity to test with consumers early to inspect what is resonating with your potential customers much sooner.
NetDevil is experienced Scrum developer in Colorado. They have fully committed to adopting agile and sent several people to the first Certified Scrum Master for Video Games course in Austin four months ago. In the article Ryan Seabury, the lead producer for Lego Universe, cautions about taking things too far with reacting to what the consumers report. This reflects High Moon's experience with early testing as well.
At best consumer testing is a gut check for the developers and especially the Product Owner on the direction being taken with the game. It also has another great benefit; When the team knows that their build is going to consumer testing, their attention to detail and polish is raised. The team looks at the build wearing their "consumer goggles".