My fiancee has an '03 RX 300 and he has had absolutely no problems with it. It's nearing 80,000 miles and the only thing that he's had done to it is regular oil changes, tires, battery and the passenger-side front window adjusted. I loved driving his vehicle so much that I sold my '04 IS 300 and bought a Certified Used '05 RX330. Granted, I've only had it for a week, but it's such a dream to drive. I'm feeling a slight hesitation in the transmission, but I understand that this is inherent with the vehicle. I'll probably bring it in to the dealer to have that checked out, but other then that I'm very pleased with my purchase. Time will tell if anything else comes up and I'll be sure to let you all know if that ever occurs.
I've always kept all of my vehicles well-maintained....I really feel that's the key to keeping your car driving into the triple digits. I highly recommend the RX!