for controllable sliding "on dry asphalt around my neighborhood" the 4 poke does much better. my 450 is VERY predictable and I slide it like nothing on dry street with like new mxr6 holeshots my banshee, with half gone mxr6 holeshots same size I have to say is scary to try to get just right to slide on the street and thats with tires that have less traction.
for me, for any racing, I'd pick which bike "I" can do better times with on the type of track the racing is on. MX I actually prefer my old LT250r or a trx250r, the lighter bike is easier for me to control to do better times, I don't have a problem screaming it to stay on the pipe so much as trying to correct the quad that weights 120 pounds more lol. not saying I don't try to bomb my 450 I can pretty easily overshoot most of the jumps, I just can come through corners with more speed on the lighter 2 smokers it seems like to me. wife said watching, I looked more controlled and comfortable and faster on the 2 smoker as well, the trx was my buddies and it was my 1st time on it and it was a race gas build and he's almost twice as heavy as me and still on his overly stiff suspension I still did better times lol
so you need to figure out which you ride better on the flat track and go from there, if you're racing money isn't an issue as you will blow through plenty of that green crap no matter what you pick! sh*t WILL break additional costs WILL come into play...