Your profile says you live in Canada so you know what the car (and SUV) sizes and capacities are like. You should also have access to a multitude of rental agencies, either down the street or on line. Somebody in the family surely owns a car. Get your suitcases together and see how comfortable the fit is for a quartet. Use that to compare other vehicles.
The other variable is fuel cost and you know or can find out Ontario prices on-line. Four passengers with luggage will increase fuel consumption at least a bit. And remember to request air conditioning. New cars have lots of electronic controls, even the base-line rental models, so ask for a thorough briefing at the depot.
My problem with rentals is that the agencies aren't good about supplying a promised vehicle and you end up in the "or equivalent" car which may or may not suit.
As a precaution take photos of any existing damage and point them out to the agent before even starting the engine.