Lights in your scene are generally too strong, overexposed areas that are strongly motion-blurred are always hard to render. The bucket one seems quite clean to me. Considering amount of motion blur, objects move so fast there's just no way in the hell anyone would notice any noise at that speed, if it's an animation and not a still frame. So either decrease strength of those illuminating materials, increase highlight compression, let it render longer, or leave it the way it is.
I doubt any other renderer would handle it significantly better. If you make scene intentionally very difficult for renderer, and just throw it on it, it will always be hard to render and will take a while. If it's supposed to be a proof that the renderer can't handle something, then that's okay, and well done, but if it's a job you need to finish before deadline, then you've got to think about how to simplify or fake some things, and how to do some compromises, in order to get it done before time runs out.