Like most electric cars, the BMW i3 is quiet and smooth to travel in. From inside the car, the interior feels and appears far more spacious than you'd expect in a minicar that's the shortest vehicle BMW sells.
The cabin is wide for the length of the car, and the base of the windshield is roughly two feet ahead of the display screens mounted on top of the dash. Overall, it feels like a much larger vehicle than it is, and its small size only registers when slotting it through narrow gaps in urban driving. While BMW says the i3 has interior volume comparable to its 3-Series sedan, the passengers sit more upright and some of that volume occurs between the steering wheel and windshield--unavailable for passengers or cargo.
The front seats were specially designed with extremely thin backs, but they're comfortable and well bolstered nonetheless. The seating position is upright and higher than some other small cars, giving the driver a good view ahead at the level of other traffic. The tilting and telescoping steering wheel has an unusual wide range of adjustment, making it possible for almost any size of driver to be comfortable.
The rear seats are tight for full-sized adults, and we don't expect the i3 to carry four people very often. They're also awkward to get to; while the rear-hinged "carriage doors" reveal a single opening without a central pillar, they're not full-sized doors and the seat actually sits further back inside than the opening. Also, rear passengers can't get out of the car on their own--the front-seat occupants ahead of them have to open their own doors first. As with most cars that have their batteries in the floorpan, the feet of rear-seat passengers sit higher than they would in the foot well of a conventional gasoline car, so there's a bit of the knees-under-chin feel to sitting in the rear.
On the road, there's almost no whine from the motor or electronics inside the cabin, except occasionally at maximum power. That's a testament to BMW's noise insulation team, because you can certainly hear a whine from the outside when an i3 passes by. The European-market cars we drove had no synthetic noise generator to alert pedestrians, and it's unclear if U.S. cars will launch with one before any Federal regulations to require it.
We did notice wind noise during our road tests, especially in gusty weather, but it wasn't intrusive. It would likely have been masked by mechanical noise in a conventional car, pointing out the different challenges electric-car designers must contend with.