My RX400h is a 2005 SEL model with 69000 miles on the clock.
I am not a car enthusiast, nor a DIY mechanic but I can give you my experience as a driver/owner in layman's terms:
1/ The car has not exhibited any major faults. Engine, hybrid system, electronics, interior, exterior are still in pristine condition. Minor niggles, the slightly less than advertised petrol consumption (at best 29-30 mpg), the short life car battery (not the hybrid engine related one), the i-phone incompatibility of the on-board telephone provision, the (excellent) computer touch screen that does not include the car stereo, the lack of ventilated front seats and four way temperature control.
2/ Major service charges are about half those I regularly paid for my equivalent M-series Merc. I have always used a Lexus garage. Last service at 60000 cost just under £200. Never escaped the Merc garage for less than £400.
3/ After seven years I can vouch for the reliability of the car/model. NB There was a batch or individual cars that had to be withdrawn or have serious factory faults fixed - I believe problems related to the steering wheel and break system computers. Check that the particular car you are interested in is not one of them or get an updated guarantee for the parts replaced.
If you enjoy driving a safe, incredibly smooth, comfortable, reliable car that can also amaze you with its reserves of power, this is the one for you.