We have a 2011 Cruze Eco, 6-spd manual, 1.4L Turbo and get 39.6 mpgUS when not using the winter tires.
Since then, the Cruze has come out with a small diesel, but it gets worse mileage in the city, better on the highway. No doubt that if you're doing mostly highway, a legit clean diesel is awesome. Not so much in the city with stop-n-go.
The daughter has our old 2006 Passat TDI Vagen that is still a great highway cruiser, like most diesels, but not near as clean as the modern, legal ones. We got about the same mileage as our Cruze Eco in a much heavier, more spacious and luxurious vehicle.
Robert's comments about fine particulates in DI gassers agrees with my tailpipe comparison of our previous F150 Ecoboost with the current RAM 2500 CTD. The Ecoboost tailpipe was black with soot almost immediately. The RAM CTD is still very clean.
If you can afford it, diesels can be cleaned up pretty good and make awesome highway cruisers. In the city, stop-n-go, doesn't seem like the right place for them.
