I have a LS600h, it’s a 2012 so is the 2nd facelift of the 4th gen LS.
Reliability wise has been great and haven’t caused me problems excluding age related issues. Suspension bushings needed replacement due to wear and I had the catalytic converters stolen but that’s not a fault of the car.
You just have to remember while it is more reliable, servicing and maintenance isn’t cheap because the car has 8 front control arms, needs 10 litres of engine oil etc etc and Lexus OEM parts are not cheap at all.
Oh and the suspension is very floaty, mine weighs 2475kg and it feels like it, same era A8L with the 6.3L W12 weighed ‘only’ 2165kg so definitely not something you can throw around.