Thanks for sharing your experience with these tools. I am only just starting to work with expressions in After effects mostly through using the DUIK character animation plugin. I have seen that After Effects has realtime output (including Syphon). I know it also has the Adobe face tracking functionality. I imagine it will be far more extensible than Character Animator but the area of realtime output and expressions functionality in After Effects is still a bit opaque to me. If you come across any useful tutorials I would appreciate the link.
best wishes,
bonemap