I traded my 2000 LS 400 for the new LS 460 and have had it for 11 days and ~350 miles. From the first I enjoyed major improvements in handling and acceleration, especially rolling acceleration. Also, the comfort of both front and rear seats is greatly improved. And, the Mark Levinson sound system with the hard disk, the navigation system, the back up camera and the park assist sonar plus a few other gee gaws are worthy additions. In this latter camp, I particularly enjoy the keyless start feature and the automatic electronic parking brake/hold feature -- what a truly great idea this brake is! The styling is attractive to me and has drawn several positive comments. I do not find the 8 speed transmission to be either a significant plus, or minus, to this point -- it is like other Lexus trannies -- smooth and seamless. Overall, the LS 460 is not quite so smooth riding as the LS 400 and I believe may not be quite as quiet, altho differences, if any, are very slight.
I cannot adequately compare the LS460 with the LS 430 as I have only ridden in the LS 430 and never driven
it. However, the LS 460 rear seat is definitley more comfortable and roomy for passengers.
To this point, I am pleased with what I see as generally significant improvements and enhancements when compared to the LS 400 I have driven for 7 years. We also have an SC 430 which we love.