Hi there,
I have a SE Navi with DAB, last car was a RX400h which I had for 34 months and 85K miles so easy to do a direct comparison.
The 450h is a far superior car, quieter, much smoother and more economical. It's not as quick on acceleration off the mark, but mid range is superb.
Forget the tales of harsh suspension that the press hacks have mentioned in their tests. Mine has the 18" wheels & stell springs, and it's fine, much more serene and quieter over the bumps than the old one.
The finish and fit is better inside, and no rattles (unlike my old 400h). The DAB system is superb, and really pleased with the ipod connection.
As far as fuel consumption is concerned, I have now done 7500 miles at an average 35.2 mpg. At 80 mph motorway runs it's returning just over 33 mpg. On my 27 mile commute from West Lancs to Bolton, it will often do 40+ mpg, but never get above 60mph. I switch to ev mode at junctions & traffic lights, and that will take the car effortlessly to 27mph, and can travel for nearly 2 miles on the flat, so reading the road, using downhill to coast & charge battery one soon learns how to get the best out of it.
I miss the sunroof and the auto tailgate I had on the 400h, but that's a minor niggle really.
Hope this helps
Regards
Roj