I'm looking forward to seeing what hyper-milers can get out of the Prius c. Keep it under highway speeds, and it should be really good.
CR's city test results are always (or almost always) much lower than EPA city ratings. Their highway is usually higher than EPA highway. But, due to their low city numbers, overall is usually lower than EPA combined.
CR's combined also includes a stretch driving in real life traffic. If you drive traffic like they have around their test facility in Connecticut, their numbers might be helpful. But the EPA doesn't do that because it isn't repeatable. In addition to seasonal differences in temperatures with an outside test track, their is also differences in traffic loads with their test. This may give a mileage number closer to what can be expected, but their numbers for models can't be fairly compared with other models tested at different times. I am too. I don't the think the manual Insight has to fear losing its crown though.