The GC3 and GCQuad are both launch monitors from Foresight Sports. They are both highly accurate and provide a wide range of data points. However, there are some key differences between the two models.
The GC3 uses a triscopic camera system, while the GCQuad uses a quadrascopic camera system. This means that the GCQuad has four cameras, while the GC3 has three. The extra camera on the GCQuad allows it to track more data points, such as face angle, loft & lie, impact location, and closure rate.
The GC3 is also more portable than the GCQuad. It is smaller and lighter, and it does not require a tripod. This makes it a good option for golfers who want to use their launch monitor at home or on the go.