as someone who has a 99 cbr 600 and i have rode with some one who had the yzf 600 they were pretty close. i felt and maybe i am biased that my cbr looked sportier than the yzf but the yzf seems like it would have been a more comfortable ride with the way the rider can site more upright. it was my understanding the yzf weighted more than my cbr but i am not 100 percent sure. i was about 75lbs heavier than the guy on the yzf and the bikes were kind of even. cbr might have been mear inchs faster. my cbr moves pretty good with a 250 lb rider against a yzf with a rider at about 170-175lb. if i remember right it was like a 2002 yzf for close to that