I replaced my 2004 RX330 with the 2010 RX350. My first impressions are everything about the interior of this car is perfect. Looks great, things are where I expect them, and the feature set smokes anything else on the road. The new 6 speed transmission paired with the 350cc engine is a definite improvement on the 330/350 from the 2nd gen and the new rear suspension makes the ride much more responsive. Exterior-wise the design hasn't changed as much as I expected, but it still looks good. I feel there are a few angles where it has a worse look to it, but most angles and lines were improved.
The Heads Up Display is a feature that exudes cool. The Navigation is quite possibly the best I have touched in a car. The blue-tooth phone integration and voice activation features work great. The star is the USB jack that allows me to control my ipod perfectly and may be my favorite upgrade.
The donut spare tire is a little bit disappointing. I am missing the storage space under the rear-cargo area from the 2nd gen.