You cannot just say Honda is better than Kawasaki or vice versa. If you will give a specific Honda and Kawasaki model then we could give you some pros and cons. But there is no one Japanese company that makes better bikes than the rest. Even if Kawasaki made a better 250F one year that could completely change by the next year. And even if the Kawasaki KX250F was considered the "best" 250F in a given year the differences are so small that only a pro level rider would even notice them. I guarantee if you took comparable models from all 4 Japanese companies to the track your lap times would be basically the same on every bike. Your 4th question is certainly a valid one though. What you will find if you read a shootout on say all 2009 250F bikes for instance, is that the RMZ250 is better suited for a novice where the CRF250R is better for a more advanced rider. So like I said you couldn't say either of those bikes is better for everyone, it just depends on the rider as to which bike is best, but again even then we are talking very small differences. I mean Ryan Dungey is no novice and he does quite well on the Suzuki. Bottom line, you can win on any of them.