I do not know about ease of use but there is a program that is free and open source called Blender.
"The first large professional project that used Blender was Spider-Man 2, where it was primarily used to create animatics and pre-visualizations for the storyboard department."
"Blender has also been used for shows on the History Channel, alongside many other professional 3D graphics programs."
"Tomm Moore’s The Secret of Kells, which was partly produced in Blender by the Belgian studio Digital Graphics, has been nominated for an Oscar in the category ‘Best Animated Feature Film"
Many open source programs can do what other proprietary software can do (if not more). So don't assume that because a program costs $500 then it must be better than any open source program.