The 2015 BMW 4-Series might have a lot in common with the 3-Series sedan, in terms of engineering and what's underneath, but it doesn't use its identical wheelbase or overall length to allow as much interior space. It's the same 110.6-inch wheelbase, and overall length of 182.5 inches, but the 4-Series' roofline is two inches lower, while it's also a half-inch wider than the sedans.
So let's get this out of the way: The 4-Series doesn't have a very useful or comfortable back seat, and it's certainly not enough for most American adults. Though it's three inches wider across the rear axle, the 4-Series still doesn't net out with much adult-sized space in the back seat, and in a tight garage its long doors don't make entry or exit very easy.
As for the front, it's a different story completely. Seating is low in the 4-Series, and you grip a steering wheel that's as thick as any SUV's; you'll learn to love the seatbelt presenter because reaching for the belt every time would lead to rotator-cuff problems. No matter which model you're considering, you'll get firm, comfortable front seats, of the sort we'd choose as desk chairs; although to be fair they don't have the same level of adjustability and side support of the sport seats (with heating and ventilation) you can get with the M Sport package.
Cargo space is great, however, which makes the 4-Series a great weekend-getaway car, or a vehicle for empty-nesters who have another vehicle for when the kids (and grandkids) visit. Trunk space is almost the size of a mid-size sedan, and storage in the cabin is a brighter spot than ever, with bottle-holders in the door panels plus real cupholders ahead of the joystick-style shifter (how did they negotiate that with the engineers?) and a decently-sized glove box.
BMW's wide, beautiful LCD screen displays crisp maps and iDrive functions, but it's also propped up the dash like a digital picture frame, something it has in common with the Mercedes CLA. Audi's A3 has a better idea: make a slide-away screen standard.
The base models, with basic black interiors, can seem drab and dark--and they amplify the 4-Series' sweeping dash curves in an unflattering way. So we recommend going with some of those spiced-up trims and luxury touches, as then the coupe's interior gets the sophisticated allure of the bigger 6-Series, with handsome leather and contrasting stitching, some daring colors and some very pretty wood and metal finishes.
The 4-Series Convertible's folding hardtop can lower or raise itself in 20 seconds, at speeds of up to 11 mph. BMW says it's fitted the folded top more effectively into the trunk this time, retaining up to 7.8 cubic feet of storage space when the top is down (or 13 cubic feet when it's up). A fold-down rear seat extends the usefulness of the trunk--and on the less practical side, BMW also fits a standard windblock, three-setting neck warmers, and more sound-deadening materials for a longer driving season and for a quieter ride than in the former 3-Series Convertible.