Their stability and reliability has deteriorated significantly.
So much so that they stopped posting uptime metrics for a while on their status page and an independent 3rd party created a website just for this:
https://mrshu.github.io/github-statuses/ (not my website)
According to that website, which unsurprisingly reports a lower number than what Github themselves claim, Github uptime is down to ~86%.
And if you work in the space, you know how terrible that is, but even more so for such a critical piece of infrastructure.
> which unsurprisingly reports a lower number than what Github themselves claim
Yes, because it throws all partial outages into one bucket, which is a dumb idea because the bigger a platform becomes with more loosely coupled components the more untainable high uptime number become.
Looking through the incidents, a good portion of them are regarding Copilot and Codespaces, two products I couldn't care about less. I do also have my regular run-ins with Github outages, but that website is just hyperbolic.