I would pick the Nissan if reliability is your top concern.
I personally don't own a car, but I am a ZipCar member here in DC. I can select from a wide range of cars to drive, among them, a BMW 328xi and a Volvo S40 T5. After having driven both extensively, it's the Volvo that puts the smile on my face. Not the BMW. I find the Volvo to be more peppy. Fit and finish on the Volvo is much better. And stock audio on the Volvo is light-years ahead of the BMW! The Volvo has never given me cause for concern, but it's also not my job to maintain it.