I've not worked with the 3.5 version of Primavera but I have been working with the V4 and V5 since half a Year now. I think the most important additions to the package are:
1 There is the possibility to undo almost every action.
2 You can now add Activity step templates to an activity so you can break up an activity into smaller steps which can help the progress process.
3 You can assign resources to different levels of the EPS so that the assigned user can only access those projects which have been assigned to him.
4 It is now possible to suspend an activity and resume it later on.
5 You can now add an unlimited amount of baselines to a project.
There are many more chnges to the latest version. For a full overview of these changes, take a look at:
