Although these notes from the field don't have all our numbers yet--just first impressions--the Highlander impressed us.
In the heaviest urban driving in our tests it got well over 30 mpg--almost twice the conventional Highlander's mileage. That was better than expected.
The report comes out in our Feb issue (but we'll probably post results sooner).
In fact, we liked the Highlander so much we got one in for our long-term test fleet (which means we keep the car for a year)--maybe we can compare notes.
I've found the Highlander very good on mileage, contrary to some reports, but as I've noted it's very sensitive to driving style. When I drive it without regard to mileage (tempting, as it's pretty quick) I get around 24-28 mpg in town; when I try for mileage I get about 10 mpg better. I've also noticed, now that the colder weather has hit, that it does worse initially because the gas engine runs continuously until it's up to operating temperature. I don't mind that, since it provides heat, but it makes a noticeable impact on mpg on short trips.
ANOTHER UPDATE: A less positive take on hybrids here, and some comments on driving style and mileage from Patrick Bedard of Car and Driver,here. Excerpt:
The other knock on hybrids is that they don't get the fuel economy promised by the EPA numbers. Oh, yes, they do, if you drive them as the government drives them on the standard test. Of course, I drove my own routes at my own speeds during my week in a hybrid Lexus RX400h. About half was on freeways, sometimes at speeds above 80; at least 75 miles were in rain. I measured 25.3 mpg over 468 miles. Maybe that doesn't sound miraculous, but when we tested a conventional RX330 (C/D, July 2003), the C/D-observed fuel economy was 17 mpg.
In fact, neither Lexus matched its EPA rating in our hands. But the hybrid outperformed the conventional version by 8 mpg.
I hope that the over-80 portions and the in-the-rain portions didn't overlap. . . . And here's more on high gas mileage as a hobby.