We have owned a 2003 RX 300 for about a month - so far, so good. Runs very quietly, handles more like a car than a truck (or big SUV), fits and finish are very good, controls and gages are well positioned, good visability all around.
We got it to tow a small boat, a task which it handles very well.
Big reasons are of course, Lexus' legendary customer service and the brand's reputation for quality.
As I said, so far, so good. Ask again in 3 years...