I previously owned a 2004 RX330 and I wish I'd have kept it. The older Lexus models felt to have some personality, these new ones dont, they're like appliances. The RX is a nice place to be however, it's one of the most comfortable riding cars I've ever been in. But that's not enough to make up for its shortfalls.
The smartkey system is one of the best I have experienced. Most cars require you to push a small button to unlock the door but here as soon as you grasp the door handle it unlocks. However I do often have problems detecting the car once I get in to start it but I believe it has to do with the fob being in the same pocket as my phone.
The nav system, especially the iPod integration. I have experienced the iPod systems in BMWs and Infiniti's and this has to be the worst. Scrolling through a playlist is painfully slow, just scrolling to the next page of 5 or 6 songs takes at least 10 seconds or more. In the BMW I can zip from the top to the bottom of a playlist faster than this can go one page. I usually end up connecting my iPhone via bluetooth and play my music that way, controlling it through the phone itself.