The 2008 Cadillac STS has comfortable front seats, but the backseat doesn’t have much more room than in Cadillac’s own CTS.
Automotive.com reports seats are "refreshingly supportive, for a Cadillac, without being overly firm," with the arm- and headrests "boosting the comfort factor a couple notches." Cars.com agrees: "the leather upholstery is both supportive and well-cushioned," with "plenty of range for different-sized drivers." Of the front row, ConsumerGuide notes "good headroom and legroom," but adds "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." The back row is another story; ConsumerGuide calls it "disappointing for a car this large."
Regarding storage space, ConsumerGuide reports that "trunk space is unexceptional for STS's exterior size...a small opening limits the size of items that can be loaded." Inside the cabin, "small-item storage is limited to a smallish center console and less-than-generous glove box."
Overall, 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." ConsumerGuide says 2008 Cadillac STS "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."
ConsumerGuide also notes that "road and wind noise are both well muted....the new V6 sounds refined when accelerating and is otherwise quieter than the engine it replaces."