PCZ is ready to be used in games. In fact, we at Liquid Rock Games are using it for our racing title and it's helping a lot. The original author Chaster wrote this for his own project use as well. I believe he is still working on the project hence being that PCZ isn't modified means that it's pretty stable.
At the moment, both Chaster and I are sharing the rights to this project. However, we are busy people hence it's been idle for a bit. However, I do intend to come back at this and add a new feature and do some fixes.
Here's the rough current state/features of PCZ:
- Two zone type (default, octree)
- Movable dynamic Portal, Antiportal (Quad, AABB, Sphere)
- Shadow map support
- Light traversal is not exactly correct. (Not noticable for the most part. Only happens in complex portal scene which means you are misusing PCZ anyways.)
- Directional light shadow map does not provide proper casting when seeing through the portal. (This one is due to the usage of portal traversal code for shadow map code. Directional light needs special traversal to get it right.)
For more info, please have a look at the docs section of PCZ source.
Just so you know, I intend to come back and do some code tidying and also add zone <-> zone filtering. Zone <-> zone filtering simply keeps a list of what zone will ignore another during traversal so traversal will stop when it hits a zone that will be ignored by the previous zone traversed. This helps in cases where antiportal culling does not work.
Also, being that zones do not share octree, using many octree zones will potentially eat up your system resources. So the advice is to use it only for large outdoor scene. For any other situation, it's better to just use the default (simple AABB check). In all respect, PCZ is designed so zones are very localized hence doing simple list AABB check would be good enough for most cases.
I hope this answers your question.