The "best" version depends entirely on your output. If you are an illustrator, Pro is likely all you need. If you are a professional comic artist or animator, EX is built to save you hundreds of hours of manual labor. At a Glance: Core Differences
Clip Studio Paint Pro and Clip Studio Paint EX are both excellent digital painting and comic illustration tools. While Clip Studio Paint Pro offers a robust feature set suitable for hobbyists and professionals, Clip Studio Paint EX provides more advanced features and functionality for professional artists, studios, and commercial use. clip studio paint pro vs clip studio paint ex
For a webcomic artist producing 3 pages a week, PRO is tedious but possible. For a manga publisher producing 150-page volumes, EX is mandatory. The "best" version depends entirely on your output