if you are under 180 lbs a 250 f (moto version)will work great. It wont be all that great for big hillclimbing or dune-ing, but for track days and woods riding they are nimble and dont kick your ***.
A 450 will feel like an apex in tight tree's( not good) If your are a novice or small in size, stay away from one( a 450) unless you have good medical insurance, and can take 4-6 weeks off work often.
If you get a 250 wr or 250 crf x it will be pokey compaired to it's higher strung brother(s) a crf/kxf/rmz or yz f.
I work at a bike shop and have been racing moto/offroad for 28 years
My opinion is
Yamaha 4 strokes 2003 to new are great, if you buy used get valves re-set before you ride it.
04-06 suzuki's are total garbage, infact all suzuki's are crap. In the racing world most pro's and or intermadiates would rather pay for another brand rather than ride a suzuki for free.
HOnda's are good bikes but require alot of valve adjusting.
Kawi 450's are great, as for the 250's, I would stay away from an 04 to 06, but the 07's and 08 were great.
Ktm's are nice but $$$$$$ now, $$$$$ later.
motocross is 95 % rider, 5 % bike, I reccomend sticking with a yzf or kxf, I'm riding a 2009 kxf 450 and it rocks.
My bike for the last 2 seasons was a 07 yz 450, it was relaible, plus out of the box performance was great.
My 05 Honda crf 450 ate valves like no other, but was killer to ride
my 2 cents
A 450 will feel like an apex in tight tree's( not good) If your are a novice or small in size, stay away from one( a 450) unless you have good medical insurance, and can take 4-6 weeks off work often.
If you get a 250 wr or 250 crf x it will be pokey compaired to it's higher strung brother(s) a crf/kxf/rmz or yz f.
I work at a bike shop and have been racing moto/offroad for 28 years
My opinion is
Yamaha 4 strokes 2003 to new are great, if you buy used get valves re-set before you ride it.
04-06 suzuki's are total garbage, infact all suzuki's are crap. In the racing world most pro's and or intermadiates would rather pay for another brand rather than ride a suzuki for free.
HOnda's are good bikes but require alot of valve adjusting.
Kawi 450's are great, as for the 250's, I would stay away from an 04 to 06, but the 07's and 08 were great.
Ktm's are nice but $$$$$$ now, $$$$$ later.
motocross is 95 % rider, 5 % bike, I reccomend sticking with a yzf or kxf, I'm riding a 2009 kxf 450 and it rocks.
My bike for the last 2 seasons was a 07 yz 450, it was relaible, plus out of the box performance was great.
My 05 Honda crf 450 ate valves like no other, but was killer to ride
my 2 cents
I guess all i care is that it has a plate 
