With the 2013 BMW 5-Series, what you see really is what you get. If you've owned other sport sedans, you can pretty effectively guess how much space there is in this mid-sizer from the outside; on the other hand, if you compare it to the mainstream models like a Honda Accord, back-seat space is clearly tighter.
In virtually every other way, the 5-Series serves its purpose well, as a comfortable, quiet luxury sedan that's fitted with some of the best materials in the business--in some cases, every bit as good as what you'd find in the 7-Series flagship.
Front seats in the 5-Series are supportive and comfortable, as we've come to expect from BMW. The seats have extendable lower cushion supports for taller drivers. Even on base models, they're the kind that you could rack hundreds of miles per day in--even with a problematic back.
For those in the back seat, leg room is an issue. The front seatbacks have a hard-plastic pocket that pushes up against knees. More to the point, the 5er doesn't have as much usable legroom as it could, given the size of the cabin and the footprint of the car. BMW 5-Series GranTurismo models have a completely different seating arrangement, and they're the exception. With a slightly elevated backseat, lots more legroom, and plenty of headroom (and a great view out), carrying adult passengers is one of the GT's strengths.
The GranTurismo has impressiv cargo space, too. BMW 5-Series sedans come with a reasonably spacious trunk, but the GT's two-piece tailgate that opens several different ways can, for those with things to haul, really put it to shame. Offering some of the benefits of a wagon without the station wagon look, the 535i Gran Turismo and 550i GranTurismo models (there's no 528i GT) offer limo-like rear seats and a flexible cargo area that feel first-class--with only the Lincoln MKT and extended-length versions of the Audi A8 and 7-Series coming close. The seats can be reclined, heated, ventilated, and stimulated with massaging functions.
On all sedans, BMW fits the 5-Siers with switchgear with lovely tactile responses and a high-quality feel. The automaker's iDrive interface remains front and center in the dash. It runs many vehicle functions and in the past has been a UI mess, but now is in its much improved fourth generation. The latest version of iDrive has a clearer menu structure and favorite buttons for some top-level categories. iDrive may no longer bring you to an impasse, but it's not always the most straightforward interface either.