 This is the second ML-350 AWD that I have owned, so my review applies to the 2012 which had engine problems, misfiring and the 2015 which has keyless go technology problems. Both items were reported to Mercedes many times and in both cases Mercedes provided no satisfaction and no ability to find the problem and repair it. On the 2012, near the end of my ownership just prior to trading the car in, Mercedes came out with and performed some sort of software upgrade on the engine and it finally fixed the misfiring. This problem had gone on for almost three years, with Mercedes denying there was a problem and telling me that it was the gasoline I was purchasing which was the same I had used in my many Lexus SUV's for previous 20 years. On my current 2015, the keyless go fails more than it works and the car continues to get confused when there are two keys near the car. My wife always carries, her key to my car when we ride together and the Mercedes keyless go is unable to switch between the keys and work  consistently. Recently, we have had a problem, where my wife was in the car and unable to get out, and I was outside with my key and unable to get in, which would have been a disaster in an emergency. The car has been in the shop at least 4 times for this problem, but Mercedes denies there is a problem and will not switch out the computer that handles this part of the technology or has been unable to fix the problem. I have made videos of the failure which I was asked by my service manager at Mercedes to do to proof the failure was happening and there are numerous reports of the problem online, but similar to my engine problem in the 2012, Mercedes is unable or unwilling to address and repair the problem. Other than the problems, we have liked the ML350, and we also own the GLK 350, but I am very unhappy with the way Mercedes addresses their own issues with their Technology. Having been a Lexus owner since Lexus came out with their SUV's and with Toyota before that, the switch to Mercedes has been difficult as their customer service and their ability to make their technology work still needs improvement. Update 8-12-17, In January 2017 Mercedes service replaced the keyless go computer and the keyless go worked correctly for a short time before it started to fail again. Now it has gotten much worse, often will not recognize one of the keys and still does not have the ability to switch between the two keys. Mercedes has a long way to go in being able to service and fix their own technology issues. I have now had this car for 30 months and keyless go still does not work properly.