I have a 400EX, all decked out for MX (no motor work, though), and a relatively stock raptor (also no motor work). I don't race MX, so I can't speak about how the two compare for jumping. I don't like the Raptor's higher gearing, but that's an easy fix. As far as reliability, the only problems I have with the Raptor are flat tires. The only problem with the 400 was impossible cold starting (due to the aftrmarket CDI box). I got used to the handling differences between the two pretty easily, but the power difference is amazing. With all that extra power, the raptor is so much more fun to ride that the 400 just sits.