Going to be renting a large SUV that needs to have good 3rd row space. Seems like apart from the Mercedes GLS450/550 which is not available for booking, the 2018 Navigator / Expedition are the best choice. Suburbans, Yukon XL's and maybe Cadillac ESVs are also available, but the 2018 Navigator / Expedition is apparently a very big improvement. I can rent the Expedition for half the rental price of the Navigator. Question is, is there enough of a difference to justify getting the Navigator?