There is NO fixed RPM engine that can convert the energy from gasoline to electricity more effectively than just driving a gas engine. The electricity from the Volt must come from from the grid, or in my case, solar panels to be cost effective. There is a conversion loss of ~30% when the electricity is sent to the wheels and then another 30% when you re-gen. The Volt gets ~36 mpg if you feed it gas alone. That's not a bad number but you can do better with other fuel cars, like a Volkswagen Jetta.
I own two Volts. I have two charging stations at home. My driving situation is that I get about ~40 miles per charge. Several times, I have gotten 60 miles out of a charge that was situational. Mechanically, the Volt seems to be very sound. With the exception of the center console electronics, everything is top notch.
An earlier poster compared the new Cadillac to an old Cimarron, My Volt, from 0-50 will smoke 95% of the vehicles out there. Electric motors don't have a torque curve, they have a torque line from 0 RPMs to 15000 RPMs in the Volt's case. I don't know this to be the case, but if they upped the battery bank, the Cadillac could have even faster take off than the Volt.
At work, we have chargers, again driven by renewable energy. My Volt was backed into the spot and right next to is, was a Tesla Model S. The front ends are remarkably similar. The back end of the Volt is nice. I find my Volt visually appealing with the exception of the black plastic body trim. But it is acceptable
The point is that electric cars can work, but you have to be in a position to make use of it.