AFAIK, the same engine ang city and jazz. I have a 09 city. Based on the on board fuel computer, I get around 16 km/l FC. I do a lot of highway driving. When I enter Metro Manila, it will go down to 15.6 km/l. The computer averages it. Since maybe 90% or more of my total km are highway, i'm guessing city driving is around 8 to 10 km/l. Mind you this is guessing. I do not compute FC manually.

If the Jazz is lighter, then it should be more fuel efficient. It also looks better. I think its a little more expensive. Maintenance should be the sme. If Honda still has supply problems due to Thailand floods, just get what is avilable.