It was funny to see this come up today. I had a LS600h for four years and loved every minute of it. I sold it when my wife and I got our RX450h a few years ago. I've been thinking about finding another LS600h or perhaps a LS500. I'm writing this from the Lexus dealer where my RX is in for a full service and I've just had a test drive in a pre-owned LS500 (around three years old, 32k miles). I am finding it very hard to pinpoint any noticeable differences between the two (beyond the obvious styling, updates to various systems/technologies, etc). The experience of luxury, comfort and general driving are very similar to me. I guess the option of spending around £47k on a LS500 or c.£10-15k on a LS600 might be worth considering too. However, both are excellent cars that, I guess, may not be being manufactured for too much longer in their current forms. So, enjoy one or the other whilst you can!