This is an excellent question. And an excellent illustration of why you need your own buyer's agent to representy you AT NO CHARGE! Local agents are familiar with builders, what if any incentives they are offering and how to get them. For instance, we recently received an e-mail that was only sent to Realtors who had worked with this specific builder before. They were offering commission incentives (which is great) but also offering our repeat clients over $20,000 in options at no charge including a fully finished sunroom. The friendly agent that you meet at the new home sales office WORKS FOR THE BUILDER. And while they can legally and ethically provide you with all the paperwork you need to buy the home, you are unrepresented.
Many new home buyers mistakenly think that dealing directly with the builder (without representation) will get them additional cost savings. That simply is not true. Builders are expecting and already have the cost of a buyer agent's commission worked into their numbers. So the only person benefiting financially if you come in unrepresented is the builder.
And who will assist you if there is a dispute in the construction phase? Who can recommend the best inspectors to check on your properties progress...and YES you should have a new home inspected at least twice during the construction process to make sure it is built to plan.
All of the above will vary by builder, location and property. Arm yourself with some great representation and get yourself the best options at the best prices on your new home!