R12.2.5 PIM looks better on the inside than on the Navigator.
R12.2.5 appears to be a far more a stable version than it’s predecessors.
The standalone instance configuration for PIM appears to be slightly less difficult as well.
Oracle has put a lot of white papers on their support site to assist in some of the security setups and configurations. Please don’t ask me for these papers on this blog. You are going to have to actually look for yourself.
The navigation paths have pretty much stayed the same so no major changes to learn.
My recommendation is to change your project plan to implement 12.2.5 instead of any earlier version. As always, don’t let your DBA patch the minimum. Be proactive and get Oracle support to recommend the patches to apply in addition to the basic installation disks.