I think the rx400h ended production in 2009, then the rx450h took over. I was looking for a rx450h, but to get one on a 16 or 17 plate I was looking at £25k-£30k. well over what I wanted to spend. Then I looked a rav4 hybrid, but at this age I didn`t like the interior too much, the 2019 onwards have a much nicer interior, but the values are still high. So I started looking at the nx300h, Much nicer than the rav4, approx £10k less than a similar rx450h and lower running costs. So when I found the right one for me I bought it.......and love it, so nice to drive, so quiet, 49mpg on a motorway run if you keep at legal speeds. What`s not to like.
P.S, I`ve driven the rx400, 450, rav4 hybrid 2016 and 2019 and nx300h. I have to say, the rx450h rides the smoothest with the softest ride, but the nx is a close 2nd for comfort and plenty large enough for most requirements.