I'm @a8m's co-founder and also a maintainer of Atlas. I don't have an exact feature comparision but Atlas (and esp the Postgres driver) are heavily maintained with advanced features like views and materialized views (functions and procedures coming up, followed by triggers and more).
What features specifically are you missing in migra? Perhaps we can prioritize them. Also feel free to join our Discord https://discord.gg/zZ6sWVg6NT
(I'm one of the authors of this project).