I purchased a new 2013 RX450h after having the original RX400h since April 2005.
Since it's been 7 model years of advancements I expected the new 450h to be more technically advanced then my 400h (it truly is), but I am amazed how much better it is overall.
The 2013 handles much better, is quieter, and the transitions from no engine to having the engine cut on are not noticeable like they were on the 400h; especially at traffic lights.
The 2013 feels much more substantial and you really don't hear the road noise or the loud engine go-cart like sounds that I could hear when I accelerated with the 400h.
I special ordered this 450h as I wanted the luxury package, the Mark Levinson audio system and Remote Start; options that the Washington, DC Lexus dealers rarely have in stock orders. My thoughts were that I wanted the options that I did not get or were not even available back on the 2006 model and I was willing to wait for my exact vehicle.
The Luxury Package semi-aniline leather is very rich looking (saddle) and the LED headlights (standard on the AWD version of the Luxury Pkg) are amazing at night and look very contemporary during the daytime.
The only negative that I have on the 2013 is that Lexus relocated the spare tire inside the rear compartment as well as the 12 volt battery from under the hood and therefore eliminated the storage compartments that were under the rear cover on the 400h. But otherwise this new 450h is truly elegant and a pleasure to drive.