For effortless gas mileage the Prius c. For hypermiled gas mileage the Prius c. For driving involvement the CR Z (especially with a stick).
CR-Z is a 2-seater. Prius C has rear seats. If you occasionally need to accommodate more than 2 people in your car, Prius C would be the obvious choice.
What are your personal priorities and desires for this vehicle? Your profile suggests you already own a Prius. Only you can determine what Priorities you value. There is quite a bit of difference IMO between a Honda CRZ and The Prius C...but which car you should purchase would depend a lot on what priorities you value. Nobody can tell you that....
I have both a 2010 Prius III and a 2011 CRZ (EX CVT w/Navi). As the other posts say, the Prius C and the CRZ are different vehicles with different purposes. I get 40-41 mpg with the CRZ as long as I resist the temptation to run it hard. I bought the CRZ primarily for styling and because the economics worked better than buying a second Prius for my short commute. I have 4 cars, so I can use it as a commuter without any inconvenience from just 2 seats. The Honda IMA hyrbrid technology is not even close to the sophistication of Toyota's HSD. It feels clunky and lurchy by comparison. You may be able to get a better deal on the CRZ than the C because the CRZs are not strong sellers. The CRZ is fun, comfortable, and I receive many complements on the styling. Good luck in your decision!
I hate to say it, but nowadays I don't think Honda and Toyota compete so much against each other as each competes against Hyundai. You might want to add the Veloster to your short list.
actually i use for 2person but sometime i go back my hometown i bring my parent along for sightseeing.is it rear seat area is too small for adult?