There's enough room for most, though leg and knee room are a bit snug. Too-flat, too-hard cushions in the front buckets, combined with a bump midway up the middle of the backrest, and a dearth of headroom in sunroof-equipped models, however, makes them less than comfortable.
The back seats, on the other hand, are surprisingly spacious and comfortable, even in the Coupe, which shares its wheelbase with the sedan. Headroom can be a bit short in the back, but is only a problem for taller occupants. Getting in and out of the back seat is the only draw back: small door openings make it difficult for large or lanky adults. The Sport Wagon, on the other hand, remedies this deficiency with longer, wider doors at floor level.
For cargo space, the Sport Wagon is the clear winner, with a massive 25 cubic feet of space behind the rear seats, or 53.4 cubes with the seats folded flat. The power tailgate makes it convenient, and a roof-rack system adds even more capacity when the need arises. Under the flat cargo floor, there are trays, hooks, and tie-downs to help secure cargo.
The Sedan's cargo space isn't bad, with 14 cubic feet in the trunk; the Coupe is a bit less spacious, but the rear seats are split-folding to open up quite a bit of room.
In general, the details--materials, panel fit, and feel--are well-executed. Some of the panels don't fit quite as well as you'd find in a BMW or an Audi, but they're close, and still very good. Soft-touch plastics, rubber-coated steering wheel shifters, and cut-and-sew leather on the dash and doors all give a premium feel. Ergonomics are generally good, too, though the location of the trip meter button makes it a blind operation while driving.
Cabin noise is also very low, which is perhaps expected in the Coupe and Sedan, but may surprise in the Sport Wagon. Wagons, crossovers, and hatchbacks (as well as SUVs) are known for their boominess, but there's very little in the CTS wagon. Road, wind, and engine noise are also very low.