"Which full-size SUVs come close to the 2014 MDX's mileage?"
If by "full-size" you mean body-on-frame SUVs such as the Chevrolet Tahoe and Ford Expedition , none comes close to the redesigned 2014 MDX, which has impressive fuel-economy ratings for a three-row crossover.
The new MDX carries less weight and uses a more efficient engine. EPA estimates for the all-wheel-drive MDX are 18/27 mpg city/highway, and the front-wheel-drive MDX is even better at 20/28 mpg.
Those numbers — which are estimates, not promises — still look impressive compared with other large, three-row crossover SUVs. All-wheel-drive models that beat the MDX's numbers include the Toyota Highlander Hybrid (28/28 mpg) and the Audi Q7 TDI diesel (19/28 mpg). The BMW X5 xDrive35d and Mercedes-Benz GL350 Bluetec diesels come close at 19/26 mpg.
Several gas-only three-row SUVs have EPA highway ratings of 26 mpg or higher, including the Ford Explorer , Kia Sorento and Nissan Pathfinder , but only with front-wheel drive or a four-cylinder engine. The MDX comes with a standard 3.5-liter V-6, and even the all-wheel-drive model has higher fuel-economy ratings than some front-wheel-drive SUVs with three rows of seats.
The Cars.com Vehicle Recommender, found here , should be able to help you sort through the many SUVs available to find the ones that offer the fuel economy and features you want at a price you can afford.