I used to ride a 96 KDX 200, stock, and then with a pipe/silencer, reeds, no airbox lid, and jetting.
Stock it is very smooth. Predictable power from idle to wide open.
After the mods it does have a bit of a "hit", but nothing like a 125 or 250 motocrosser. If I had to describe the power I'd say the low end of a 250 and the topend power of a 125, with an almost seemless blend between the two. Very fourstroke like, very mild compared to a two stroke motocrosser.
Now my 220 is so smooth and hitless that it's boring. It doesn't rev, at all. When it seems like the hit should be just about to come the bike falls on it's face, zero topend. It's like a 4 stroke playbike, only it takes premix. Now, with the right mods they are supposably much more snappy and more motocross-like. I'm still waiting for a few more minor parts (and the snow and ice to go away) and I'll know this spring how well it really opens up. I've treated it to Fredette porting, headmod, and bored carb, as well as an FMF rev pipe, Turbinecore II silencer, Boyseen reeds, and a hacked up airbox lid during the cold and snowy season.
I'd have to say stock-vs-stock I liked the 200 much better. It was great in the nastiest rocks and mud, and more fun on wider trails than the 220. I've riden a DRZ and felt like it was big, way big compared to the KDX. And the KDX doesn't feel all that light and nimble compared to a motocrosser, although it's easier to ride in about any condition.