While the Cadillac CTS has filled in as a rival to both compact sport-sedan models like the BMW 3-Series and those a size larger like the 5-Series, the new ATS is entirely a compact and taking on the 3-Series, Mercedes C-Class, and Audi A4.That gives the next CTS, due this year, a chance to grow; and it permits those who don't plan to pack adults into the back seat (at least not for too long) a more compact sport-sedan option from Cadillac.
The ATS measures 182.2 inches long, and rides on a 109.3-inch wheelbase—so it's not really any larger than compact sedans like the Chevy Cruze or Ford Focus. At 55.9 inches tall and 71.1 inches wide, it's a relatively petite package all around, and at least relative to sport sedans of the recent past, Cadillac is proud of the ATS's low curb weight.
With 42.5 inches of front leg room, 33.5 inches of rear leg room, and 10.2 cubic feet of trunk space, the ATS checks in about even with most of its competitors for cabin space. Its base front buckets are good enough to be compared to the German school of firm and fine; the optional performance seats have very supportive backrests, are thinner in profile, and have adjustable thorax bolsters and thigh cushions. If there's no sunroof, the ATS has decent to good headroom for a six-foot adult, with good legroom in front.
In back, it's where you'll need to consider your priorities. There's simply not enough useful space for average-to-taller adults, and even getting in and out can be tight. The slightly larger A4 and the noticeably bigger BMW and Infiniti are closer to practical for regular adult use. From the same overall length, BMW seems to have extracted more usable space inside, and much more trunk space.
That said, the ATS does offer up a lot of places within the cabin to store smaller items. Just behind the CUE infotainment screen is a storage bin almost 2 liters large; it's big enough to hold phones, tablets, or radar detectors.
Another thing the ATS gets right is the details—in terms of trims, materials, and the look and feel of everything. At least at the base level, the 3-Series feels built to a lower cost. In the ATS, real magnesium shift paddles, the haptic interaction with CUE, the coordination of CUE's graphics and icons across both its screens, even the high-quality look of the base leatherette interior all speak to a level of attention that mostly escaped today's CTS. If there's one detail the ATS is lacking, it's the rock-solid door-closing sound of some old-school German sedans.