I'm always more inclined towards steam because its the better launcher in aspects of not causing issues with windows. I've actually had to throttle back to windows 10 from 11 due to launcher issues with epic-games and battle-net. It will forever be a pet peeve for me not being able to have all my games in one unified launcher. However, I can't exactly argue with the offers and sales that come up on EPIC. I got GTA V for 1/4th price as opposed to usual from EPIC, and some people got it for free.
With respect to functionality and ease of use - god steam is a clear winner. With respect to sales, games launches and updates - everything else pretty much.
I've also moved your thread to the appropriate board.