I have owned most luxury brands, and this is by far the best car I have owned (I got the Modern Luxury package with SmartAccess). I tested the others, but the Lexus was simply in a different league. Ride quality is extraordinary-- both smooth and quiet. The interior is exceptionally well crafted. If you cannot get comfortable in the LS 430's seats, you simply cannot get comfortable in any car. Performance is better than I expected. The LS 430 does not have quite as many technological gadgets as the Acura or Infiniti, but it certainly has enough.
The quiet, smooth ride. XM satellite radio. Not having to fish for my keys.
I would have preferred the navigation system to have better voice activation and that radio and climate work off voice activation, as well. Other cars seem to have slightly larger navigation screens. These are quibbles.