I'm thoroughly enjoying the learning process in Poser 5 (especially the new renderer and Material Room, which I feel are the heart and core of P5), but I won't be using it as my primary application until some of the bugs, quirks, and stability issues are patched. Until then, I'll continue to use P4 for most of my work. Hopefully, by the time the major problems are fixed, I'll be comfortable with all the new features.