I have roughly 1200 miles on my rx400h. I do a 40 mile commute to work on the I-495 beltway around DC. This drive goes from highway speeds to a slow crawl at a moment's notice. While there are many things I don't like about the rx400h
( the navigation software and lack of ability to change a destination or dial-up a phone number while moving), the mileage has been pretty true to the claims so far. Averaging between 27 and 29 according to the display. I do around 65mph on the beltway when traffic permits and many cars are flying by me at 80 mph.
These people are the first to complain about gas prices at $3.59 per gallon, yet operate their vehicles inefficiently.