Id get a 450 you would probly get bored of the 400 pretty quick.
And in my experiences with bikes hondas always handle the best and are a good overall machine. Yamahas are a good mix of handling and power. And Suzuki usualy has the strongest motors and decent handling and suspension. Ktms are always the fastest but i hate the european suspension. Im tall so i always feel like im riding up over the bars on Katooms. And Kawasaki just sucks in my opinion. Too bad they had to merge with Suzuki haha. This all changes year to year of course so it realy all depends what year bikes your talking about.