I'm normally that guy that buys a used bike and get to test ride it for a short time and if I like it I buy it and customize it later to make it really work for me. This is my first review and it had to be done. I didn't get the chance when I was buying my FIRST Bran new bike. So I spend a lot of time researching which bike I was going to buy because I plan on racing it in the AMA Gold Series but also trail ride with it. So I hope this review can help others. Here is a short back ground, Currently own 05 Honda CRF 450, 99 KLX 300, 84 Honda 250R, 04 YFZ 450, 06 Suzuki LTR 450, 89 Honda TRX 250R, 86 Honda TRX 250R, KZ-11 Ninja, and a few other street bikes. AND my new 09 YZF 450. I also have ridden the 09 CRF for 3 days and 06 RMZ 450 lots. You can see I'm not bran loyal and ride what I like. I'm 5'7 180lb. I have raced quads in the B class for a few years and start riding dirt bikes 6 years ago, do lots of trail riding and raced several times. I'm going to start with Suspension and handling, incredable! I'm blown away how much control you get with this bike. It comes out of corners like it has a pit bull on its hind leg. I have a track at my house and there is one particular corner that no one of my friends or I has been able to put a rut into (even when its muddy). Even my next door neighbor who was a pro rider (He is on a 06 RMZ 450). After one week of riding I now have a rut from the YZF doing its job. This is the summer time when the ground is hard!! I did have to adjust my suspension a little softer for my track and tried it out on the trails at that setting also. Like every review I read on the suspension was true, Fantastic! Definitely nicer than the CRF 05 and 09. The 06 RMZ 450 is shorter in lengh and handles really well in turns but for a longer bike on the YZF it wins on cornering but not by much. The brakes work extremely well specially with the wave rotors in front and back. Body and weight, its much slimmer than any of my other bikes and feels great to move your body around. Its very light on the ground and in the air. The 09 CRF is thinner (much) and feels lighter in the air because of how much you can move on the bike than than the YZF, but pretty equal on the ground, they do weigh about the same. Since I am a short guy I was very concered about the bike being an inch taller than any of my bikes. It was noticeable, as soon as I got on I was on my tippy toes to get myself and the bike upright, and it was also noticeable riding it. After a few hours it didn't seem tall and through the corners it wasn't a big deal because my bars were only inches from the ground because of how well it turns but, until I was coming to a stop and had to put my leg down I was back on my toes. Trail riding was a breeze and effortless I could have adjusted the suspenion a little softer but compared to my CRF I wasn't worried about it. Power, this is the one place I was really having a hard time making up my mind. I know the CRF's are fast bikes and all the reviews on the YZF said that they were slow, but had great throttle control and said riding was much easier. Which was really something I was interested in because I wanted to ride longer on my 05 CRF but got tired out to fast because of hard white hand gripping acceleration and hard breaking because how fast you would come into things. This is so not true, the 09 YZF has power and lots to give. Not as much as the 09 CRF but pretty close. The power feels good everywhere but more so in the mid range were I like to ride. After getting into the high rpms and let right off the gas it will pop several times like there is a exaust leak at the head or lean on the top. I'll be investigating this later. My 05 CRF has a hair more power than 06 RMZ and 09 YZF beats the 05 Honda every time. (it might be the other rider, but I also feel that the YZF is faster when I ride it). The throttle response is so much smother and cleaner and throttle control is much easier. I'm able to ride 20 mins longer and not nearly as tired as I would be on my CRF. The YZF is making ruts everywhere! it just loves chewing that ground and spitting it up but grips at the same time! My 05 CRF has a full Yosh on the exhaust and the 09 YZF sounds almost idenitcal, they also start the same. The sound range is in the high 90's, I would have liked the low 90's. 09 YZF is easier to kick over and warms up much much faster. I did buy a Flex fuel screw and put that on so I wont have to take the tank, seat, and motor mount off to adjust the fuel screw. (A MUST) Just like my 04 YFZ its a pretty sensitive carb. I also regreased all the bearings ( A MUST) Overall a great bike to rideon the track and in the trails. I am hoping that the 2010 will be even better with all the changes. 09 great for me and very happy about the purchase and well worth the $5400 after tax, setup and lic. I know I couldn't resist the great price you can get one for!!!