The Terrain GMC should be your best pick if you prefer a smaller, portable car to drive comfortably but if you are a family person with kids, you should opt for the Acadia. The Acadia is more expensive than the GMC Terrain; it has three rows of seats that can accommodate seven passengers, while the Terrain GMC has only two rows that can accommodate only five passengers. The exterior part of the Acadia is around 75.4 wide, while the Terrain is 72.4. The Acadia is also taller than the terrain, with 66.7 to 65.4, respectively.