The styling, interior, and luxury features are all substantially improved over RX300. Handling, turning/parking, cornering, overall power better too. Cruises at 80+ wonderfully. BUT, annoying manifold buzz (even after recall); brake rotors needed turning at 12K and 25K miles; transmission downshift lags badly at low speeds (i.e. accelerating suddenly from 15-20 MPH). Almost all units have 18" wheels with very expensive, short-lasting tires (mine are gone at 31K, $800+ to replace). I believe that quiet ride is sacrificed with the larger wheels and lower-profile tires. Lexus still can't get auto-climate control right - my 10- yr-old S500's is truly "set and forget".
In-dash CD changer, telescoping steering column w/memory, auto-dimming mirrors, damped open/close for all interior compartments, wood/metal trim, illuminated gauges (change intensity according to ambient light), audio on steering wheel, rear legroom, NO ASHTRAY!
Tighten up transmission, stronger brakes, take 18" wheels out of all packages, make tilting RV mirrors easier to override, make tow-hitch standard