not quite accurate .....

......the 450 x is heavier but I can probably , no let me change that I can go anywhere you can go and 80 mph on a dirt bike is just a plain gas to ride the gravel roads .

1st gear will do very technical trails and you won't believe the grunt the big thumper has

hills are no contest for the 450 you don't have to get your motor running so to speak to tackle the hill just turn on the gas and tractor power takes over and up you go !
get into some wide open spaces and most assuredly the 450 does like to stretch it's legs

, and man can she run ,the suspension soaks up hard stuff at speed superbly !The 450 in my opinion is the ultimate woods bike , she has got bottom grunt and at speed you think someone replaced your 4 stroke with a two stroke . she's really really fast .
oh yeah the valves aint an issue on the 450 like they are with the 250's , time will tell all though .
If you can't afford back tires quite often you won't like the 450 because she is a TIRE EATER (rear only)
The 756 dunlop dies a quick death on the 450 . lots of tire spin.
The 450 is sweet best of both worlds !
c-ya****mustang