Hey Phillip,
Thanks for reaching out!
If you scroll down a bit on this page, you will see a side-by-side comparison of what features come with the Core plugin, The Events Calendar, compared to what features come with Events Calendar Pro.
Now, to be clear, you do not choose the free version “OR” the Pro version. The Core plugin is The Events Calendar—it must always remain active! Plugins like Events Calendar Pro and Community Events are add-on plugins that add-on to that main core plugin. So to use Events Calendar Pro, you install The Events Calendar and Events Calendar Pro. You then add Community Events if you want.
As far as Community Events itself, it does not offer anything that is in Events Calendar Pro. It also does not offer anything in The Events Calendar.
Community Events simply adds a front-end submission form for events. That is all.
I hope this information helps!
George