Is using an auto broker better than using a car buying service?

Not exactly. Car buying services (like Costco Auto or TrueCar) connect you with a dealer at a pre-negotiated price, but you still complete the purchase at the dealership and may still face the finance office. An auto broker handles the full transaction: sourcing, negotiating, paperwork coordination, and often delivery. The level of service and the degree of insulation from the dealer experience is typically higher with a broker.