I've heard the RF's are good for drift but still grip pretty well. I just wish they'd come out with something in the mid 80's duro in the GOS shape for a freeride wheel. I love the shape, but not the duro.
Imo, the duro is fine for what it is. (Though I am a light weight, so that probably does alter things a bit.) Another awsome freeride wheel are the Loaded Purple O'tangs. I can't stop drifting all over the place with these wheels. Though the only downside with these wheels is that they die FAST. Even for someone like me who has problems wearing wheels just because I don't weigh enough, I notice that there is a bit of coning only after 2 sessions on them. If you can hang on tight, I think Loaded is coming out with freeride wheels in the future, but I wouldn't hold your breath for that. And of course, there is the classic old 'thane blue Kryps for freeride. Another wheel I really enjoy freeriding though are Orange Landy Hawgs.