on all the mag tests the yfz isnt much slower than ktm and if u end up buyin a yamaha its cheaper and u can make it faster than the ktm for the same price as a stock ktm
yamaha definately. ever look at the kawasaki's? i'm not a kawa man so idk too much about them, but i've ridden with a kid that had one and he was beatin most other 450's in drags.
from what i've read it sounds like if money is no issue than the KTM is the way to go but if you are looking for the best bang for your buck than the YFZ is what you want. i'd go with the YFZ.
on all the mag tests the yfz isnt much slower than ktm and if u end up buyin a yamaha its cheaper and u can make it faster than the ktm for the same price as a stock ktm