The 2013 Toyota Prius is rated at a combined 50 mpg, and it will likely deliver that--or close--to most drivers. It will keep up with fast-moving traffic if you run it hard; at steady highway speeds, the engine is relaxed and the traveling experience is pleasant. That ends when maximum power is required, when you'll hear frequent howling as the engine runs up to its maximum speed and stays there.
The 1.8-liter four-cylinder engine is mated to a pair of electric motor-generators inside the Hybrid Synergy Drive system, which supplement the engine power, power the car solely on electricity at low speeds and under light loads, and recharge the nickel-metal-hydride battery pack (stored under the rear deck) during regenerative braking. Noise and vibration from the engine are well suppressed under most circumstances, except if you hot-rod it too often, as described above. That kind of treatment, however, drops the gas mileage from the high 40s to the mid- to high 30s.
Roadholding is is decent despite squealing on hard cornering from the low-rolling resistance tires. As in most Toyotas, the electric power steering is lifeless, limp, and betrays no sign of road feel--though it works fine, and energetic drivers will find they can hustle the car through competitive urban traffic. The four-wheel disc brakes work fine under the circumstances when they take over from the regenerative battery-charging under harder stopping.
Pure acceleration isn't swift, with a 0-to-60-mph time just under 10 seconds--but that's not why people buy a 2013 Prius. The experience behind the wheel in a Prius is so different, with electronic control of virtually every aspect of the running gear, that drivers are much more likely to focus on increasing their fuel economy number than on beating others away from the stop light.
And careful driving, planning ahead, and using the lower-powered "Eco" mode will let any driver exceed 50 mph in city driving. Toyota also provides an "EV" mode that directs the car to power itself solely from the battery pack until it exhausts its 1 mile or so of low-speed electric range.
The Prius Plug-In Hybrid performs just like a regular Prius, but its larger lithium-ion battery pack provides longer electric range (the EPA says 6 miles of continuous range, and 13 miles total) and electric-only power at higher speeds (in our experience, drivers can see all-electric propulsion up to the high 40s if they use a very light foot).
The charge-port door is on the right-rear fender, and a full recharge using the 3.3-kilowatt onboard charger takes about 3 hours on conventional 110-Volt household current, and less than 2 hours from a 240-Volt Level 2 charging station.