Have been driving the GLK250 since the end of June '13 and have had no major complaints so far. Zero problems (mechanical or electrical) encountered and it's simply a solid vehicle overall. Have been averaging 30-31 MPG after 5 fill-ups in 80/20 Hwy/City driving. That's from my own mileage calculations but frankly the on-board trip computer is not too far off (within 0.5-1MPG accuracy). I'm not exactly a lead-foot but I don't drive like a granny either (I'm 28 years old). This thing just eats road imperfection for lunch - I live in the NE region so there is plenty of that around. Can't wait to test out the 4Matic performance in the snow in another month or so.
I love driving this little SUV. It has the Premium 1 package but no Navigation. I have been enjoying the diesel experience so far. After 16,000 miles, my MPG average is 31.1, pretty impressive compared to the published 28 MPG. I do not purposely drive slow to get that MPG number. I average 60/40% HWY/CiTY. My advice is to find the cheapest Diesel pump as it usually sells most diesel and keep the fuel fresh.
GLK 250 is a great ride with excellent gas mileage
written on 02-19-2016
The only drawback to this vehicle is the tire noise from the run-flats installed as standard equipment. Otherwise it is a great vehicle with no problems, recalls, or dealer involvement. Tire and wheel warranty already executed for a leaky rim, but quickly replaced at dealership. The tire noise remains, and no apparent resolution is being offered as a remedy.
I'm getting 33 mpg in mixed driving (more than the EPA estimate, which is common for diesels). The quality is exceptional. My Mercedes dealer is making sure this, my first Benz, will not be my last. No complaints. One quibble: turn the radio off and the backup camera goes off, which is crazy. Ignore that eccentricity, and this is a perfect SUV.
I traded in an MDX looking for something a bit smaller. I had looked at the 2012 GLK but was really put off by the cheap interior. I was happy to see that Mercedes really improved on the interior quality for the 2013 GLK. I was a bit skeptical at first about the engine seeing as though it's a 4-cylinder, but it has an amazing amount of torque and when you hit the gas you'll feel it. It has plenty of passing power at highway speeds as well. The 7 speed transmission is very smooth.