Just rode an '08 YZ-F 450 back-to-back vs. '07 CRF450 @ 4200' altitude...interestingly, the jetting on the YZ at this altitude (clear day, low relative humidity) was spot on....As the bike broke in, I could start to draw some comparisons: The yamaha has a small, almost compact feel (and I'm only 5'8''/165#) to it and would turn underneath anything on the track. Incredible front-end stick, doesn't want to stand up in the ruts, etc...I would have to say it rivals the Suzuki in turning prowess. The suspension has a firm, well damped feel to it, but still too green to make any final judgments...definitely equal, if not better than the Honda, especially on rough corner exits. Brakes are awesome, with great feel, and the clutch is light with superb modulation. Trans shifted quite stiffly, I'm hoping that will improve with time (as is usually the case with Yamaha).
Now the power: The Honda initially felt faster, especially in the lower mid-range...As the day wore on and several of us switched off riding the 2 bikes, it became apparent the Yamaha and the Honda were dead even in the amount of power from the upper-midrange to the rev-limiter (both with stock exhausts). However, at the very bottom, the Yamaha has just a bit more, then it is flat for a bit, then pulls hard with a nice hit. I love that hit, as it allows me to turn with the rear wheel and pivot out of corners. The Honda's power is more linear, very smooth, but no hit, (IMO) which I crave. I actually use LESS clutch with the Yamaha as I tend to run a gear high, then use the clutch to pivot out of the turns. The power characteristics really reminds me of a 2-stroke YZ 250, about '01 or '02. So, in summation, I personally liked the bike, it fits me and my riding style well, so I am picking one up next week.
As for the pipe, I'm leaving it on, because they can't hear me coming!
Its amazing to me how some people think this bike has good low end power and hit. This bike has NO HIT at all. The power is so smooth and lacking, its the furthest thing from having a hit.
To address the guy that says 5% of the people on here can use 100% of the power is not right. If the bike is slow its slow. If I turn the throttle wide open and think to mysef I wish this was faster then I would say im using 100% of the power at that moment.