I have had this 2010 Lexus RX450H for about 3 months. One thing disappointments me is the actual mileage I am getting. I use it for commute from home to work in San Francisco. So far the total mileage is 880. I have been getting 21 MPG in city and 23 MPG in the city. My combined average MPG is 21.9 MPG. The advertised fuel efficiency is 28 MPG on highway and 32 MPG in the city. Not sure it is just my car or it is the city that has lots of hill and traffic signal. My round trip from home to work is 12 miles. One reason we want to switch from our 2001 BMW330CI (which runs 14 MPG) to this car is hoping to save gas. I have not bring this car to long trip yet, will test that out later.
Living in SF you're guaranteed to have 20-30% less fuel mileage than a flat area. The hills are hell on mpg. I had a smart car- it got 21 mpg. Rented a Prius and got about 28. It's just the rough side of gravity. Can't live with it, can't live without it.