The Acura MDX SUV is considerably larger and more expensive than the RDX SUV, while the RDX is more maneuverable. Both vehicles use very similar V6 engines in their base trim, but the version used in the MDX is slightly more powerful.
The 2015 versions of the Acura MDX and RDX share many similarities from a visual standpoint, with the MDX appearing to be a scaled-up version of the RDX. The larger size of the MDX gives it an additional 7 cubic feet of cargo space over the RDX and allows the MDX to seat seven passengers versus the RDX's five. However, the RDX has slightly more front headroom and rear legroom than the MDX and is also more maneuverable due to its smaller dimensions. The 3.5-liter engine used in the MDX produces 290 horsepower, while the RDX's version produces only 273 horsepower. Despite this power difference, both vehicles achieve a fuel economy of 23 miles per gallon in combined driving.
The MDX and RDX differ significantly in pricing. The MDX is priced from $55,340 as of July 2015, while the RDX starts at $38,880. The price difference is partially due to the size difference between the vehicles, but the MDX also includes some standard equipment not found on the base RDX. Many drivers also find the ride of the MDX is smoother and more refined than that of the RDX.