You are right the Lexus interior is lot nicer. But, only two drawbacks cargo room is way too small on the RX330 vs. the MDX. Also, horsepower. RX330 only got 230hp vs. the MDX 260hp.
From what I heard the 2005 MDX would have 280-290hp 3.8L. Nicer interior, more sporty, HID lights, side curtains airbags.
RXKICK.