I would be happy with either.
As Suman says, if you need the larger boot and don't spend too much time stuck in traffic, I would say opt for the 460. If you are undecided, then drive both and go with your heart. I have had Lexus cars since 2001 and I have yet to worry about reliability issues. Yes there are issues if one searches hard enough but having also run Mercedes cars I can honestly say Lexus has been far less stressful !
Have been running an RX400h since 2005, no battery issues so far! Whats more there are more than a few Toyota Prius taxi cars out there with 300,000 miles on the clock.