"I bought a 2015 GLK 350 AWD 4 moths ago and have 4,000 miles on it. Overall the car is great. It drives well with good visibility (tight handling and responsive). The interior finishing is impressive and comfortable. Overall combined mileage is about 24mpg. Mercedes customer service and follow-up is excellent.
The only downside is the navigation system. For example, you can't take a look at the upcoming turns, miles to next point or the total itinerary. Mercedes apparently realized this was an issue and upgraded it on the new C class. I called them to ask if a hardware/software upgrade would be made available for the GLK and they said it was not & they weren't sure if it would be. So on long trips I need to use my iPhone and the Google maps navigation function to get this information"