Big acquisitions rarely play out the way people want to. Microsoft has a spotty record on this front with lots of their acquisitions killed off or limping along. On the other hand, their current CEO seems to be a strategic person and I kind of like how he has transformed Microsoft in the last few years.
So, from that point of view, this is probably not that great. The good news is that Github is based on Git and it is easy to move away from it. My current project moved from Bitbucket, to Gitlab, and eventually to Github. The most annoying thing about these moves is dealing with issue trackers, CI and other stuff you need in any decent project. I actually wrote a script for migrating bugs from bitbucket to gitlab when we did that, which I believe is still there.
The reason we did that move was performance. Bitbucket performance was just horrible at that time. We self hosted Gitlab for about a year and that worked fine but self hosting adds a lot of complexity and cost. So, eventually we moved to Github. I've been generally quite happy with it. I also enjoy that most of the OSS community seems to be on it. So it acts as a loose social network where I can follow projects, issues, and developers. I never got that on either gitlab or bitbucket. These social features are what make Github valuable.
From a functional point of view, it's clear to me that I want my source code hosted for cost reasons. I also need performance, reliability, and integration features. Github ticks those boxes so far. If MS doesn't ruin that, I'll likely remain a paying customer. However, Gitlab has caught up and is pretty much a drop in replacement from a functional point of view. But they do lack the social dimension. They have the tools but not the people.
Also worth mentioning that you can host private repositories on keybase and that they have some team features in the work as well. If you are looking for alternatives.
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