Small luxury SUVs are one of the fastest-growing luxury vehicle types in recent years, representing 21.8% of luxury vehicles sold this year, Edmunds data show. That compares to 8.7% in 2009.

Driving this trend are models such as the Acura RDX and the Cadillac XT4.

Acura was one of the pioneers of this class of vehicle with its RDX. The 2019 RDX is fully redesigned and is one of the brand’s most popular models. Cadillac, for its part, has introduced the all-new 2019 XT4. It’s the brand’s most affordable vehicle – SUV or otherwise.

Picking which one to buy can be difficult. Both the RDX and the XT4 are priced to start at less than $40,000 and offer a comprehensive set of features. Edmunds takes a look to find out which one has an edge.

Starting price

Lower prices, relative to other luxury vehicles, is part of the appeal of an entry-level luxury SUV. If you go easy on the options, you won’t need to spend much more than you would on a well-equipped non-luxury model such as a Chevy Equinox or a Honda CR-V.

The XT4 starts at $35,790, including destination fees. Acura asks a bit more up front for the RDX – $38,395, including destination.

Both the XT4 and the RDX offer a decent amount of standard luxury appointments including power-adjustable front seats, simulated-leather seating and crisp-sounding audio systems. The Acura has a few standard features that are options on the Cadillac and help justify the higher price. These include a power liftgate, a panoramic sunroof and more-advanced driver safety aids.

Various option packages can run the prices up in a hurry, however. A fully equipped RDX just clears $50,000, while the XT4 is $55,000-plus.

Technology

The Cadillac XT4 and the Acura RDX differ in the way they require drivers to interact with their infotainment systems.

Cadillac’s XT4 takes a traditional approach by combining a clear, easy-to-use 8-inch touch-screen interface with a redundant rotary control knob. The Cadillac’s available navigation, head-up display and optional Bose audio system are easy to understand as well, making the XT4 a comfortable and familiar vehicle as soon as you get in.

Acura’s RDX takes a distinctive approach with its interface. Eschewing both the touch screen and the familiar control knob, the RDX uses a touchpad interface to control its 10.2-inch display screen. It’s an intriguing but challenging system to master and could put off less tech-savvy buyers.

On a more positive note, Acura’s available 16-speaker ELS sound system will impress even the most discerning audiophile.

Power, economy

These two SUVs use similar powertrains. Acura’s RDX has a turbocharged 2.0-liter four-cylinder engine that generates 272 horsepower and returns an EPA-estimated 24 mpg in combined city/highway driving. With the RDX’s optional all-wheel-drive system added, efficiency drops to 23 mpg.

The XT4 also has a turbocharged 2.0-liter four-cylinder engine. With 237 horsepower, it’s less powerful than the RDX’s engine. But in return, you get better fuel economy. Expect 26 mpg in combined driving with the front-wheel-drive XT4 or 24 mpg with all-wheel drive.

Both manufacturers recommend using premium gasoline to ensure these fuel economy and horsepower numbers.

On the road

To make the most of these engines’ power and fuel economy, Acura and Cadillac have engineered transmissions with an almost unbelievable number of gears. The RDX uses 10 speeds, while the XT4 employs nine. In our experience, the Cadillac feels just as quick as the more powerful Acura around town. But it’s not quite as smooth since its transmission can be slow to downshift when you need a quick burst of speed.

An adaptive suspension, available on both the RDX and the XT4, allows the driver to tailor the vehicle’s ride quality to match personal preference or road conditions. With it, the RDX manages to soak up road imperfections while maintaining confidence-inspiring stability.

The XT4, on the other hand, often feels busy and jiggly over less than perfect roads. The Acura is also sportier when driving around turns and gives you a better feel for the road.

Both models are impressively roomy for both front and rear passengers. But you might like the Acura a little more if you frequently need to transport a lot of gear. Its cargo area behind the rear seats measures 31.1 cubic feet compared to the XT4’s 22.5 cubic feet.

Edmunds says

The Acura RDX and the Cadillac XT4 are solid, stylish choices in the competitive small luxury SUV segment. Though its infotainment system is one of the more polarizing on the market, and could very well be a deal-breaker for some, the RDX gets our overall nod thanks to its smooth on-road manners, powerful engine, and slightly lower price when fully equipped.

Kurt Niebuhr is a vehicle test editor at Edmunds.