I heard that the first Lexus RX model (RX300 with a 3.0 liter engine) had sludge problems that caused early engine failure.
The wife has the RX330 and apparently Toyota/Lexus fixed the
problem. I have been a long time Toyota fan, but they are not immune to problems.
Many vehicles have problems, if they admit to them and fix them then fine. If they hide them like VW did with their, I think 1.8 or 2.0 ltr engines then it's a crime.