No drivetrain problems at all. This has been a defect free car since we bought it. The handling is fantastic, very Porsche like in that there is a great balance and ease in cornering. We also have Infiniti g37xS and Lexus Rx in our garage and I can say the Mazda 6 is a very impressive car. I suggest getting leather seats if you are considering the 2016 model as the fabric they use traps fibers and is extremely hard to vacuum clean. I have physically scrubbed the lint while vacuuming and it is still hard to get fibers off as they penetrate the seat fabric and stay trapped. Highway gas mileage is 36 of you stay at 70 and use cruise. This is a well built car and terrific value. Stay away from the model with the regeneration feature as it requires a deep cycle battery that costs $300 to replace.