To be honest, I've had a few issues so far, but nothing a bit of creativity couldn't fix. I spent the day doing test renders to see when to use the P4 vs. firefly render engine. For the most part, firefly isn't that great. If you want to do close ups of the new hair, then you'll want to use it in Production Mode for the final render, but I'd stay away from it otherwise. The content is great. Folder organization is so much better! (I was almost sobbing with joy at nested folders!) They've made it easier to work with objects and their properties. (The mouse disappears on me when I do that, but if I move the mouse, it comes back.) Some of the strand based hair models look quite nice, though I think a mix and match between old and new types would work best. I'm very happy with P5, but I do think we're kinda gamma testers. Software isn't released - it escapes.