I test drove the Highlander Hybrid around a month ago. It drove nice but you heard a lot of engine noise. It was much louder than the RX400h. The car had a lot of power though. When you pushed the gas, the car literally just took off. The CVT transmission really makes a difference. You should definitely test drive one because it is way different than driving a normal vehicle. Personally, I don't think it is worth it if you are buying one because for the fuel economy. However, I do think it is worth it if you are spending the extra money for performace. The better gas mileage is just an added bonus. It is sort of like shelling out the extra money for a V8 4Runner over a V6 but there are different factors to consider in this case. As for the interior, I am really not a fan of the wood trim. I think it actually cheapens the look. I also think the materials used in the 4Runner are better quality than those used in the Highlander.
Overall, you really can't compare the 4Runner to the RX400h/Highlander Hybrid. They are two totally different vehicles. The seats in the Highalnder/RX400h are much more comfortable and the ride is smoother than the 4Runner but I like everything else better in my 4Runner.
If you want to see a more detailed review of the RX400h, see this thread I posted:
http://www.toyota-4runner.org/showth...threadid=12278