Coming from 2005 RX; I had compared with 2009 MDX, 2009 Veracurz, 2009 ML350, 2009 MKX. 2010 RX350 was best for what I/wife needed. AWD. Gen 6 Navigation, adoptive headlights, comfortable drive [standard 18s], and perfect size [not too big or small] were primary reasons for the purchase. 2010 RX is noticeably improved in reduction of noise from both wind and road. Power and gas mileage is probably best in class as I have averaged 20 in mix driving. And suspension is not too hard or soft and it is perfectly tuned for what I want. Steering is another huge improvement over the 2005 and it is no longer light but has little more feel.
Gen 6 navigation beats all knob controlled navigations from other makers. Ride quality and sound control. Perfectly sized for what we need. Cool/heat seats. Back and side design.
Light on overhead console. Toxic plastic smell during first week. Smell was so bad the first week we had to drive with windows open with A/C. Full size spare should be standard on all AWD.