The pro version have morphs & material controls, and you can load more than one model in the scene. Plus there are built-in motions & special effects specific to Pro version. Some of the XPS models have different bone structures, you'll need to use the bone mapper to be able to use motion on them. Here's a video about bone mapper:
It's annoying to use the bone mapper when using it standalone. Is it better to use Unity or Blender?
Some xsp models can be used as they are, so it may depend on how the creator made them.
Does the demo version limit the frame rate? If you use Quest1 standalone, it is unavoidable that the frame rate is low in terms of performance.
The demo version is free and I think this performance is amazing.
I'm interested in the pro version. However, the performance cannot be fully brought out by stand-alone use.
My hope is to have VRM and other support.