I haven't rode either one so i don't know. But Dirt wheels( don't mean much) did a shootout on the both of them and they said the ltr was best.

 

The dirt wheels test was determined for the track since those 3 are supposed to be track ready off the showroom floor. My buddies 450R does real good on the trails and such. Personally i would love to have an R450 but it's to new for me to personally buy one. Look what honda and yamaha did to their 450's 1-2 yrs after they were introduced. So give Zuk time to figure it out (even though they did work on it for 3 yrs) and it'll be just as good as these newer "updated" yamaha and honda 450's. So go with the YFZ if you're buying now the Zuk is just to new IMO