We use GH and are investing more in the platform features.

Codespaces specifically is quite good for agent heavy teams. Launch a full stack runtime for PRs that are agent owned.

    >  keep hearing that Github is terrible

GH is many things to many teams and my sense is that some parts of it are currently less stable than others. But the overall package is still quite good and delivers a lot of value, IMO.

There is a bit of an echo chamber effect with GH to some degree.