My .o2cents.... P5 is much more difficult to use, IMO, and also much slower... It loads slower, renders slower, imports textures and mats slower. the library tree takes longer to load. I have an AMD XP1800+ CPU..which is 1.53ghz..512meg ram. Having said that, the final result looks better in my opinion...there are many more options. I did not buy the Pro Pack, and now I have all those features as well. One of the things I like the best is the ability to actually see the text on the dials...P4 was such a pain. the multiple views are very nice..The ability to use a scrolling mouse on the library is very nice. The library itself is arranged much better...you can click right on the folders to open everything. P5, in its basis, is the same as P4, and I guess with the addition of the Pro PAck...you then get the additonal features, new render engine, etc.... As a final thought, had I not purchased P5, I doubt very much that I would have missed it all that much. Its still pretty much the same game with some added frosting, which makes the program overall a lot harder to use and master. Many folks will probably not agree with my take on P5...but I'm still using the same models, same clothes, same hair, and so forth that I had in P4...I got much more done in P4, as well..mostly because of learning the new rooms in P5...applying materials to the models....attempting to make hair...etc...and of course the slower render times... I also had a lot of problems early on, but most of them have been cleared with the recent patch releases. CL is working very hard on correcting the problems. Its your call, and quite frankly, I think if you're an avid Poser user, even though casual, a fairly tough decision to make...would I buy it if I had known what I do now??? Very doubtful....but I haven't gone back to Poser 4 since I got 5....so I must like it a bit :) Its a challenge, maybe...and the end result of your work gives that wow feeling quite often...as you experiment and try different things, there are many moments of great discoveries...little shadows that change the quality of the render, finer detail, better lighting...new tools to use... If you do decide to upgrade, just be patient...read the manual...plus you have the added benefit of having some of the questions answered already..there are tutorials...lots of xamples, and some folks that can already answer many of the questions.

Humankind has not woven the web of life. We are but one thread within it.
Whatever we do to the web, we do to ourselves. All things are bound together.
All things connect......Chief Seattle, 1854