There are good improvements in Bryce 5 over Bryce 4. Bryce 5 does not install over Bryce 4 so you can have both on your harddrive. I found no use other then to port my presets and plugins over to 5 so I have deleted it without problem. The instablity is a comparable thing. Bryce 5 is much more stable then most 3d applications it is less stable then 4, but 4 was considered a rock by many people more then just myself. Bryce 5 has options that help with render quality, It renders closer to highend quality applications now then it does to vue which renders with much less accuracy and very poor anti alias. Also remember that Vue uses shadow maps to make shadows so the shadows in Vue will by nature be less accurate. Things like radiosity and image based lighting are pretty easy to fake in Bryce but impossible to do with Vue. The best thing to do is to download the demos and see for yourself. One thing I have learned this last year of 3d is. Don't believe what you read, many reviews are poorly written or written by people without enough experiance to give a program a proper work out. If you are a person that pushes Bryce (any version) Bryce 5 is for you. If you are a person that finds Bryce hard and rarely goes beyond the defaults the perhaps Vue is for you. Either way downloading the demo's is the only way to know. Griggs