The is absolutely no reason why anyone should talk you out of a LS460, it is obviously a upgrade car for you and a nice one at that, lots of talk from other on your post about the LS400, ive had a couple of 400s (over 10years ownership) and loved them but upgraded to a LS600hl which apart from the hybrid side is basically a 460 although mines the long wheel base with every bell and whistle supplied by lexus ie relaxation package but as i said just a 460 on steroids lol, it s a lovely car and far far superior to the ageing 400s, every car on the market will have its niggles over time.... so in my opinion i say go get the 460
ps the 460/600 isn't the right car for anyone worrying about mpg, coz you dont get much lol,