That's the reason you hear the complaints: they're from people who no longer want to be using this product but have no choice.
Because Microsoft doesn't need to innovate or even provide good service to keep the flies glued, they do what they've been doing: focus all their resources on making the glue stickier rather than focusing on making people want to stay even if they had an option to leave.
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
I do not doubt people are having issues and I'm sure there have been outages and problems, but none that have affected my work for weeks.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.