Updating from a 2007 RX350 to a 2013 RX450h has been a mixed blessing, though overall I'm very pleased with the newer car.
Performance in sport mode is quite adequate while even in the more sluggish Eco mode there is no trouble overtaking or darting into gaps in traffic. Economy has seen a big improvement, as one would hope when upgrading to a hybrid. The old car averaged 12.0 L/100km over its life, while the new one sits at 7.8.
The ride is a bit more jittery than the old car, though it handles better. "Better" being a relative term - this is no Porsche Macan!
Still, the RX is not meant to be a track-day special - it's designed to waft a family about in a pretty good level of luxury. The interior is very smartly presented, with all the bells & whistles you'd expect at this level. Lexus throw most things in as standard, but there is no options list. If you want more equipment you need to shell out substantially more for the next model up. Having said that, the entry level Luxury grade lacks for very little. Some additional safety kit such as active breaking and lane assist might be expected.
The quality of some interior components (some of the switchgear, arm rest, glove box lid) has taken a step backwards, and the cruise control lever is still Toyota standard.
The seats are big and comfortable with multi-way adjustments. However, those on my RX350 Sports Luxury felt slightly bigger and more plush, with a better quality leather. The back seat are great, with more than enough leg room, 40/20/40 split fold, reclining backrests and fore & aft adjustment. A very nice place to be for a long trip.
The big boot has lost a lot of nooks, crannies and under-floor storage. The spare wheel is now mounted inboard instead of slung under the body LandCruiser style. And it's only a space-saver. This combined with multiple batteries means that there is virtually no storage for odds and sods. In the cabin, storage is good with a big centre console (which could make more effective use of its space) and very big flip-open door pockets.
The Lexus ownership experience is pretty good. 12 monthly service intervals, and not ridiculously expensive. "Free" loan cars are included, as well as a very high level of attentiveness from the service staff. The current car has just hit 30,000 km and the previous one had 107,000 km when I sold it. Neither car ever had anything go wrong - utterly reliable.
In summary, the RX450h is a very nice, very pleasant place to be. It's not a sports car but is not meant to be. It's my second Lexus and probably won't be my last.