I had the opportunity to drive 3 of Lexus Hybrid drive vehicles yesterday in their "Drive the Future" event. I started with the LS600hL. The back seats are nice, and the shiatsu massage function is great, and I like the way that the entire dash was covered in leather, instead of the plastic from my LS460, but to be honest, I found that the car was noisier than mine, and (shock horror) did not feel as fast. while the boot was even smaller, it was not so small as to be unusable, but was certainly not befitting a car of this range.
I also took the opportunity to drive the GS450h and the RX400h. They drove similarly, and I decided to get a new RX400h SE-L for my wife to replace her Renault Scenic