about the 2009 model's reliability, ease of maintenance and fuel economy?

It is a bit early to say anything about this specific model as it so new but the basic drive train I believe is based on the M class SUV. Mercedes had some issues with the M class in the early years but the vehicles produced over the past 5 years have been outstanding for initial and long term quality. Mercedes in general has really gotten its act together starting in about 03 and is truly once again producing a world class vehicle. The GLK is a very sharp design and the one I drove handled very nicely even on rough roads. Great visibilty with no blind spots, (unlike the M), and I loved the firm solid ride typical of german cars. I would not hesitate to buy this vehicle if I was interested in a luxury small SUV and I bet it will hold its value nicely.