[jfim]

I actually purchased Satisfactory on their release date and it was rather underwhelming.

The core gameplay loop is very different between both; the one in Satisfactory seems to be more about building some automated set up, then exploring while things are building, as the factory production seems rather slow. In contrast, the core gameplay loop in Factorio (increase the production of whatever input is currently starved, build new more complex set ups) is clearly more polished and engaging, IMHO.

Of course, that could change, Satisfactory is still in early access and it seems that they've been more focused on adding new environments and gameplay mechanics than touching the core gameplay loop. Satisfactory is also a lot better IMO with regards to exploring stuff, just like Subnautica.