The 2010 Cadillac STS may sit in a larger size class than the smaller CTS sedan, but its interior doesn't offer that much more space. Reviewers at TheCarConnection.com and around the Web put the STS's comfort, utility, and quality in the low-to-middle end of the luxosedan pack: it's softer and more luxurious, but with average fit and finish and lacking the room its rivals have in ample measure.
The STS's front seats rival those offered in the German competition. They're amply proportioned and very supportive, with plenty of space in front.
There's "good headroom and legroom," ConsumerGuide says, but "some testers feel hemmed-in by the wide center console and high windowsills." However, "the standard power tilt and telescopic steering wheel helps dial in a comfortable driving stance." Cars.com agrees: "the leather upholstery is both supportive and well-cushioned," with "plenty of range for different-sized drivers." The only exception comes from a Car and Driver reviewer, disappointed with the hard plastic at the edge of the STS's center console, which "still bruised our knees after just a few hours of driving."
It's the backseat that disappoints: it's barely roomy enough for average adults. ConsumerGuide calls it "disappointing for a car this large," and TheCarConnection.com's editors note that legroom is surprisingly tight for a car so generously proportioned otherwise. Don't plan to carry full-frame adults back there on a regular basis.
The trunk's only slightly more usable, and a decently sized console and glove box offer some small-item storage and hidden cubbies for iPods and portable music players. "Trunk space is unexceptional for STS's exterior size," ConsumerGuide says, and "a small opening limits the size of items that can be loaded." Inside, they add "small-item storage is limited to a smallish center console and less-than-generous glove box." Edmunds chimes in, reporting "the trunk is also smaller than what one might expect for this class of car."
Build quality in the 2010 Cadillac STS isn't particularly grand. ConsumerGuide says the STS's "interior materials quality is good when compared to domestic-branded premium sedans but falls just shy of the standards set by German and Japanese rivals." Cars.com finds the Cadillac STS interior "comfortable and lined with respectable materials," but notes "execution leaves a lot to be desired," adding that "most of the flaws could have been fixed with a modest freshening, something on par with what the outside received."