The XT5 is the most important Cadillac on the market - and it has just one problem

It's all fairly low-key and should attract a lot of buyers who've been waiting for Cadillac to offer a solid crossover to tempt them away from BMW, Mercedes, Lexus, and Audi.

Notice that the XT5 isn't a chrome-a-palooza. Also notice that the Cadillac badge is tastefully scaled. By far the most hulking thing about the vehicle — from a marque that still sells that very hulking Escalade SUV — is the tail-light design.

Everything else is calculated for broad popularity.

The interior of the car is, in a word, fantastic. It's roomy. It's luxurious without being too much. It isn't an orgy of topstitching and bright chrome. The materials are all excellent, premium, supple. The leather feels really good.

You could argue that interiors are really where the action is these days with upscale crossovers. On the outside, it's questionable whether there's much to be gained by going with a crazy design idea — everybody who wants to buy one of these vehicles seems to be seeking the same thing.

Case in point. Massive sunroofs are becoming standard equipment on luxury crossovers. This isn't an exterior design feature, not really.

We like 'em because they prevent the back seat from having a cave-like quality. They also give kids the chance to stargaze at night and cloudwatch during the day. On jaunts to big cities, they can also look up at skyscrapers.

This is debatable, but Matt thinks the Cadillac Cue system, after being complained about initially, is the best in the business right now, surpassing even Audi's infotainment setup, which we have frequently praised in the past.

What makes Cue so effective is that the touchscreen interface is simple and intuitive; both Apple CarPlay and Android Auto are available; voice commands work well; the navigation is excellent and well-integrated with OnStar; and wireless 4GLTE connectivity means that an entire car full of people can use their devices on the road. That's an amazing package.

It's annoying. We prefer vehicles that have a nice, old-fashioned P-R-N-D shifter, not one of the newfangled joystick-y deals that can confuse you about which gear you're actually in. Caddy isn't alone in using this tech, which saves space. But they don't have it in their new CT6 flagship sedan, a car we recently tested. We very much liked the familiar shifter in that vehicle.

This is one of those small details that we really appreciated. Having a dedicated place to stow your phone where it can both be seen and charged is helpful.

From this position, you can connect the the infotainment system via the USB port, and if you use Apple CarPlay, bring Siri online to experience the premier voice system in the auto industry. That's right — Apple CarPlay in a Cadillac brings out the best in Siri.

Why would you want to put your phone anywhere else? In the cupholders, it just rattles around and prevents you from enjoying a refreshing beverage.

Note the clean nature of this center console's design, by the way. There's brushed metal, a simple arrangement of buttons to control driving features, and a pair of cupholders that can handle just about any standard beverage container, be it cup, can, or bottle.

OnStar had been around for decades — it was one of the first connectivity features to show up in automobiles. For a while, it was derisively considered by some critics of the tech as a way to unlock your doors remotely, if you locked your keys in the car. Or as a way to call for help if you drove into a ditch.

But as connectivity had become much important with the advent of the internet, OnStar has been able to unlock some unforeseen value. It's helped GM get out ahead of the competition. And of course if you want hands-free directions, you push the blue button and talk to an actual person — it's the fastest and safest way to obtain navigation.

White has become Caddy's signature color, thanks for the "Dare Greatly" ad campaign, with TV commercials that show white cars floating through a gray downtown New York landscape.

This color allows some of the details in the bodywork to stand out, such as those slight ridges in the hood.

There's more than enough space back there to use the XT5 for as an upscale weekend utility vehicle, to send it to the mall to load up on threads and flatscreen TVs, or to take it on a weeklong road trip with a family of five.

For the most part, we enjoyed looking at the XT5, sitting in the XT5, listing to Sirius satellite radio in the XT5, using CarPlay in the XT5, driving kids around in the XT5, and going to the grocery store in the XT5.

But we didn't enjoy the combination of a 310-horsepower, 3.5-liter V6 engine and an eight-speed automatic transmission, even when we put it into manual mode and used the paddle shifters behind the steering wheel and pepped up the driving mode.

This bugged us. A premium crossover with a decent-size V6 should have been oomphier.

We asked Cadillac to explain. A spokesperson told us that Cadillac's "engineering’s team was aiming to get the best real-world fuel economy and day-to-day usability for buyers in the market segment," adding that fuel economy ranks really high in owner surveys."

This confirmed our theory. We didn't think there was anything wrong with the engine, but we figured that Caddy had gone for MPGs—18 city/26 highway/21 combined—over performance. But we also thought that the issue could be solved by dropping in a turbocharged four- or six-cylinder powerplant. Cadillac told us that there's no plan to do this in the US, sadly.

The XT5 hauls you from 0-60 mph in a Caddy-claimed 6.6 seconds, and it had a reasonably competent all-wheel-drive system that should be able to handle the worst the suburbs throw at it.

We've sampled all the premium audio systems on the auto market, and while some are more dynamically interesting than Bose, and some really make you feel as if you're in a rolling concert hall, Bose Surround Sound will please almost any driver or passenger and can handle any type of music, from heavy metal to New Age, pumping it all blissfully through 14 speakers.

It hits a sweet spot. You just can't find anything to complain about.

Sure, Ben and Matt were slightly disappointed by a few aspects of this new crossover, but for the most part the XT5 is a solid offering in its segment. Compared with the competition from Acura, Lexus, BMW, Mercedes, and Audi, its interior truly sets it apart.

And it's about time Caddy got its act together with this genre of vehicle, easily the fastest-growing in the luxury marketplace. Nice work, but with some room for improvement.

The good news is that it's currently the most popular vehicle Cadillac is selling, besting everything else in the portfolio, with sales of around 4,000 in June, after an April rollout.