If you "just want to render stuff" stick with 4 or get the Pro Pack. If it loads and doesn't lock up afterwards, P5 is good for: Making hair (not easy and very slow to render) Dynamic clothing (also very slow) Playing around in the material room Making funny faces Stay away from P5 if you make scenes containing more than three or four mil figures. It slows to a crawl after that. I can get 10 to 15 in a scene with P4/ProPack. Also stay away if you work long hours in Poser. P5 will eventually clog up and require you to exit and restart. It might even require a reboot. I've worked all day in P4 without that trouble. I have not seen a whole lot of improvement in renders with Firefly, but it is a lot slower. Of course, all of this is just my opinion/experience. You may have a much more pleasant one...or much worse. I have a dual pentium 4 xeon 1.7 machine with a gig o ram and a 100 meg hard drive.