In front, the wide, flat-bottomed seats are excellent; they don't have much side support but they give the type of support that's good for all-day drives. The driving position in the C-Class is quite good, too, between the telescoping steering wheel, the power driver seat, and the car's tall, glassy cabin. C63 AMG models have similar packaging but get snug-fitting AMG sport seats that will keep you pinned in place in the corners.
The rear seats still are one of the most significant drawbacks of this car. Somehow, Mercedes designers either ran out of space between the front seats and the trunk, or they assumed C-Class buyers won't be using the back seat, but available space back there isn't adequate for most full-sized adults. Average frames will have enough headroom to be comfortable but will still be short on legroom; and taller adults will have to contort to fit in. The trunk is a little small as it is, at 12.4 cubic feet, but this time around Mercedes-Benz didn't forget about interior details; there are plenty of cupholders, door pockets, and a sizable glove box, plus a big center console.
While the base C300 does include some barely luxury-grade plastics, overall the C-Class models come with distinctive materials and excellent fits and finishes. Cabins are well hushed from road and wind noise, though you do hear the engine more than some might expect in a luxury car (Luxury models are quieter).