My experience since a few months ago on a project (not a game):
1 - Limited to a certain file size
2 - Highly unstable
3 - Slow feedback and if you have a few of them in the scene can bring the editor/sequencer to a crawl.
4 - Issues with motion blur and velocity channels.
5 - I can’t imagine it being used in a game unless the object cache in question is of a very limited optimized size and length.
Personal take: For an engine that advertises itself for VFX use, in comparison to Unity’s geometry caches implementation it is very very poorly implemented here.
- We dropped UE4 switched engines to meet expectations and schedule for the project.