With leather upholstery and a high grade of standard features in even the entry-level models, the IS is a luxury sedan from the start, and the typical Lexus materials and build quality will meet most people's baseline standards for the price.
Despite the pleasing interior styling, the car's not especially opulent, even with the optional wood trim packages, and though the front seats are roomy and well-padded, the rear seats are cramped and short on headroom and legroom both. The Auto Channel points out the IS's sport seats provide "very good side support, to hold the driver and passenger in place if the driver gets too energetic." They note, though, "rear legroom is tight." Edmunds similarly advises "adults or even large children may not be happy in the rear seat on long road trips." The Orlando Sentinel agrees, saying the 2010 IS is "comfortable up front, a little cramped in the rear." Kelley Blue Book also backs up the consensus, noting, "Comfortable and supportive power front seats" but "modest head and leg room" for rear seat passengers relegates it to kids-only duty.
Edmunds calls the interior materials "impressive," with "handsome design [and] impeccable fit and finish." There are downsides to the cabin of the 2010 IS: "Coarse-surface tire thrum is noticeable but not intrusive. Wind noise is modest," comments ConsumerGuide.
With 13 cubic feet of cargo room available in the sedan, the IS isn't too short on space despite its mid-size sedan class. This is due largely to the shape of the rear trunk lid, which "aids aerodynamics and also increases trunk room," according to The Auto Channel.