Pro Will be very easy for developers already familiar with Python
Although it's possible to use only C++ to program in Panda3D, all its power is available to the Python scripting language, while not trading in performance since the performance-critical parts are implemented in C++.
It has a powerful binding layer that exposes the vast majority of the API via Python-based interfaces.
Con Loading Panda3d will change your builtins to contain non explicit references to non-standard helper functions
A lot of the pollution comes from storing global state. Instead, you can store and update the global state of a namespace instead. As for the built-in pollution, you can make a wrapper that backs up builtins, imports pandas and then restores builtins, though this may not work as pandas almost certainly uses its extra builtins to work. The best thing to do would be to explicitly import the same objects that are in the builtins over the top of the modified builtin namespace, although it doesn't remove the code smell, it helps to make things look less (if not at all) magic.
Con No unified editing program
Unlike Unity and Unreal, Panda3D doesn't currently offer a single, unified editing program in which objects can simply be dragged in and assigned properties (although third-party solutions are available). Developers are expected to design their scenes in a modeling program like Maya or Blender instead, and import them into Panda3D using Python code.