I spent 6 months looking for a used reliable luxury car that could do 40,000 to 50,000 of highway kilometres yearly without bankrupting me (no, I am not an Uber driver). My choice was between the Genesis G80 and the Lexus GS (I was initially looking for Lexus LS460 but I could never find one that was in WA where I live). It turns out that the Genesis G80 cars I've tried had weird chassis vibration issues at highway speeds, which turns out to be a well known problem according to my local Hyundai dealer.
I bought a used Lexus GS450H with 50,000km on the clock after my W204 C200 Mercedes was written off when a Mercedes dealership crashed it.
I drove the Lexus for about 6000km of mainly highway kilometres in six weeks. Long story short; it is a great car as a used car but no way I would be paying near $120,000 for new.
Interior: The front seats are not very comfortable. I find the leather a bit hard and it feels like the seat frame is made for small bodies. If you are a bit overweight like myself you would be okay but not super happy; this is a $120,000 sedan, and you should feel happy with it. Everything else in the interior is super high quality, elegant and well organized. There is button for everything.
Exterior: This car is the Queen of understated luxury. No one would ever recognize that this is an expensive car. You would not attract an unwanted attention. It's a very cohesive design.
Engine: It's a 3.5-litre direct and port injected engine running Atkinson cycle, naturally aspirated. It sounds good, and drives smoothly. It is basically an advanced version of usual 3.5-litre Toyota corporate engine. It should be reliable but maybe not to the extent of the regular base version with port injection only running Otto cycles.
The car has a planetary gear set, which is super smooth but has no shifts - like a CVT but without the rubber band effect. I personally would've preferred an 8-speed ZF box.
Cabin Isolation: There is a weird omission here - no double pane side window glass! The cabin is well-insulated from wind noise and engine noise but maybe the tyre noise is a bit too prominent for a Lexus. It had a set of Dunlop Max Sports, which I replaced with Pirelli All Seasons. That helped, but only partially.
Ride: I have a general opinion about Lexus in general (I also own an RX350); they excel at making soft riding cars. Using relatively simple suspension technology with no air suspension or any crazy adjustable dampers (magnetic ride - looking at you GM) and that makes their cars reliable. But, they are crap at imitating the Germans in making sporty riding cars, and that's what happened with the GS.
This is an E-Class competitor with double wishbone front suspension, independent rear and adjustable dampers, but no air suspension. The car is pushing 1900kg with one of the shortest wheel bases in the mid-sized luxury car segment and this gives you a confused ride. The ride is not soft enough (like the ES or even the LS) but also not sporty like the 5 Series, and that leaves something to be desired, which is not acceptable for a $120,000 luxury barge. This car desperately needed air suspension to compensate for the heavy weight and short wheel base.
Hybrid system and fuel economy: It's reliable and there is an 8 year warranty on hybrid components from Lexus. Fuel economy is 6.3 litres per 100 kilometres; My W204 Mercedes C200 was doing 8L/100km, so I have no complaints and am very happy.
Tyres: The size is 235/40/R19. The tyres are too low profile, and the car is sensitive to flat spotting. Lexus please stop imitating the Germans with super low profile tyres; I think more side wall would have helped the ride a lot.
The steering wheel is pulling to the left constantly which was not fixed by wheel alignments and balancing at two different shops.
The active cruise control: when a car in front of me on the highway comes into my radar range the car starts to accelerate and decelerate repeatedly, and ever so slightly, until it reaches the desired distance behind that car. I've compared that to a few other Lexus active cruise control systems (albeit on an older 2011 model RX) which were very smooth unlike my car.
I hope I was informative enough and did well on my first ever car review.