Hi. As a recent user of Cycles 4D, I must say that for me, its the perfect render engine. Its a modern pathtracer, designed from the start to be a production capable renderer. I´ve been exploring its set of features during 3 weeks. At the begining, my thinking was "as a render engine, Cycles is a little naive". But I dont think so right now. It´s fairly easy to setup render settings to achieve the desired quality/speed. IPR works quite well, only dont think you can go with a full speed IPR window at 1280x720. ¿Dou you know of another rendering engine that can show volume rendering of fire and smoke in an IPR window? Cycles can do it. All in all, Cycles4D its the perfect companion for X-Particles, no doubt, and a serious and well suited rendering engine for VFX. ProRender for Cinema4D looks like a wellcome upgrade from Advanced/Physical render. So no doubt I will like it.