I went through the same exercize. The X5 although a great car failed in several items. Most important in my opinion was the cargo capacity which is about half that of the 330 when compared by square feet. Second was options, several options are not available on the X5 or not as effective such as 6 CD changer. In the X5 is trunk mounted, dealer installed and very high price, nav system on X5 hard to use with a mouse like input using a button below the screen. No adaptive speed control, mileage lower, dashboard dated, tinted windows only as option with Sports package, basic X% reasonably priced but builds up pretty fast with options needed to match 330. Last but not least, from reliability studies the X5 needed more repairs than any Lexus product according t Consumer reports. So, in my honest and humble opinion. You get more for your $$$ with the 330. If you however must have that BMW badge in front with the perceived but not always evident perormance then the X5 is your choice. The very limited cargo capacity is what kept me in Lexus when I needed to replace my RX300