Where the RX 400h had extremely light steering, it gets stiffened up a bit for the RX 450h. Steering wheel buttons include voice command, which lets you dial phonebook entries from a Bluetooth-connected phone by name.
One particularly interesting aspect of the RX 450h is this new interface controller. Moving the square joystick moves a cursor on screen, and the enter button selects applications. It is very similar to the interface on a PC.
The new home screen offers this simple row of icons for choosing different functions in the car. It's easy to use, but we don't like that the interface lets you move the cursor all over the screen rather than locking it to the icon row.