What are the differences between TV Sony XBR400 and 450?

I would like to know what are the differences between TV 32" Sony XBR 400 450 model? Please give me some inputs.
Thank you very much

The XBR450 has 2:3 pulldown which the XBR400 and HS20
do not have. This is suppose to provide fewer artifacts and
cleaner pictures with NTSC sources (The Perfect Vision
The XBR450 also progressive scan inputs. I own the KV32XBR400 I am very happy with it. My signal source is a RCA Directv reciever conected via Monster Video3 S video. This television looks great with HD brodcasting and DVD.