I was skeptical of the mileage, but I was getting approximately 40 mpg in the coldest part of the winter and 42 mpg when the temps were in the 40s. Recently the temps were in the 50s - 70s, and I've been getting 49 mpg. The Civic is my commuter vehicle and I drive 42 miles to work and back each day on country (45 mph) and highway (65 mph). I'm in Ohio so it's generally flat. I also do not accelerate rapidly.
Fuel efficiency. The dashboard is great for providing real-time feedback on how you're doing in the fuel efficiency area.
I would like the vehicle to have dual visors as sun is a problem sometimes. Even my old Ford Taurus had them.