'06 to '08 MX models hard to beat the RM250 for value for money. Outstanding handling chassis and cheap to buy new, nothing will cut to the inside turn like the Suzuki. Good engine as well. Makes a damn good off road bike too.
More money to spend and want a light light bike go the SX250 would be my next choice although the engines have been tamed down in these years and that could be a good thing if you want to double duty it for off road (you haven't really mentioned what sort of riding you want to do, bearing in mind all these MX'rs are aimed at riding Super X). If I didn't have the Suzuki option I would use one of these and use it for a light weight off road bike with some work as they all would need for my use.
The Yamaha would be the only other I would consider on merit of its engine being similar to the RM250 and decent suspenders but doesn't handle as quick as the Suzuki and its a bit dated looking and the blue plastic gets tatty very quickly.
Honda never finished developing the last generation of CR250's and the engine performance is a weak point along with the electronic engine management, jetting, vibration through the bars causing arm pump and foot pegs that feel too far forward creating a cramped riding position in my opinion and I'm traditionally a front end rider. If you are scared of the front end as many riders are and hang of the back that might not be a problem for you.
Kawasaki is also an outdated looking machine and its green with a funky linkage with those older AOSS forks and would be my very last choice, in fact I probably would never bother to go riding if I had one of those. Rather ride one than a Gas Gas though and thankfully they don't make a 250 MX'r (I hope) lol!
Just my opinions!

Good luck with your decision.
Bookmarks