Someone asked me what I thought would get better fuel economy in city driving, the hybrid Toyota Prius C (a.k.a. Aqua) or a new 1.2L Mirage.
The answer is: it depends (TM)!
-- Driven "normally" in the city by an average driver, the Prius C will get better economy. This is mainly due to the Prius engine start/stop programming, which is much more "aggressive" than the Mirage's start/stop system (which is only available in Japan/Europe anyway, at this point). The Prius engine stops running when the accelerator is released at speeds as high as about ~60 km/h/~40 mph, so it wastes no fuel idling or when coasting (under most conditions).
-- The second reason the Prius would beat Mirage is due to its electric assist/regenerative braking, where the car captures braking energy into the hybrid battery and can then use that energy to move the car at light/moderate load and low speeds on electric power alone (e.g. when stuck in traffic).
-- That said, a manual shift Mirage driven by a motivated eco-driver/hypermiler would challenge a Prius C, but it would involve a lot of manual engine-off coasting. It would be a lot more demanding on the driver, and arguably harder on the Mirage's 12 volt battery, which isn't really designed to support the extended drains that type of driving would subject it to.
I took part in an economy run in Montreal last year, and in my 1.0L 5-speed Honda Insight with the hybrid functions completely disabled was able to beat a team with a Prius C. It was a combination of suburban/rural driving, not a hard core city route.
Noteworthy: in Japan, the only cars with better fuel consumption ratings than the Mirage 1.0L with auto stop & go are the Prius C and Prius Liftback: 1.0L Mirage/Space Star: best non-hybrid fuel economy in Japan (JC08)
Of course, the Prius C starts at $19,875 in the U.S. vs. around $13k for the Mirage. So if saving money is your goal, you'll have a very hard time (impossible?) getting the Prius C's fuel savings to make up for the lower purchase price of the little Mitsu.