I have owned a 2019 Sonic Titanium RX450h since December last year. It is classed as the RX + Premium Pack, but I believe very close to Luxury trim of the past model years. What impresses me most is the ride and interior quality, and the comparative silence to all other cars I've previously driven (despite being an SUV).
I used to have an Jag XF with adaptive suspension, and in my opinion my Lexus without it is more comfortable than the Jag. I find it comfortable to drive on all road surfaces, particularly on the motorway - it eats up miles for breakfast, dinner and tea 🙂 I've not long returned from a 1000 mile trip up to central and western Scotland, and it was a joy to drive.
The interior quality is fantastic in my opinion, very well put together with high spec materials. The seats are terrifically comfortable too with heated/cooled settings, etc.
The only minor criticism I have is there is perhaps a little 'float' when driving at speed on fast, twisty A-roads (but then I just slow down a little 😉), but this may be mitigated somewhat by the adaptive suspension.