The 2015 Volvo S60 may have been the middle of Volvo's sedan range before the withdrawal of the compact S40, but it's on the small side for a mid-size sedan. As compact luxury models like the Acura TSX, BMW 3-Series, and Mercedes-Benz C-Class have gotten bigger, it's much closer to their size than to that of a BMW 5-Series or Infiniti Q70 (nee M). It makes good use of its interior volume, and there's plenty of room for passengers in the front and adequate room in the rear.
The new front seats introduced for 2014 are some of the best we've ever occupied in any car. They're substantially bolstered--and we worry that wider Americans won't quite fit into them--but after a few hundred miles of driving, we had no aches, pains, complaints, or any other issue. They're the kind of seats we expect in the highest-end sport sedans, and often don't get. Well done, Volvo.
The back seat looks tighter from outside than it proves to be once you get in. It's well contoured, although the raked rear window means it's closer to the floor than taller adults may like, leading to a slightly knees-up position compared to taller sedans. But it will hold passengers over six feet tall--two of them, anyway, if not three. Trunk space is also voluminous, as you might expect from the high tail and fastback-like line of the rear bodywork. The rear seatbacks, split 60/40, fold forward and also include a pass-through for skis.
The S60 isn't the single quietest car we've been in, but it's hushed under most circumstances and noises from wind, tires, and road surfaces are mostly well-suppressed. The car offers a wide range of chassis settings--firmness can be set to Touring or Dynamic, and increased driver control is available through Comfort, Sport, and Advanced modes.