GitHub is the most mainstream, Gitlab has the most features and is selfhostable, Gitea has fewer features, but is more lightweight for selfhosting. Both Gitlab and Gitea are also working on federation.
I don’t know about the others.
Both Gitlab and Gitea are also working on federation
… and aren’t owned by Micro$oft, which is always a huge plus.
Github is the industry standard. It’s easy to use and is packed with features, it’s also quite flexible in how much it provides for free.
Codeberg is a github clone but open source and nonprofit. People are weary that github is owned by Microsoft so if you’re a privacy conscious person that likes open source, it’s a good option.
I’ve never used Gitlab but from what I’ve heard it’s more enterprise oriented, focused on providing solutions for companies rather than something simple for everyone. You can also self-host it if you want it on your own servers.
codeberg: KISS
It’s a matter of opinion and lots of it depends on your preferences.
Github: Where most developers are and therefore has the best network effect. Easy for new contributors. Gitlab: Got some traction after Microsoft bought Github, but is very similar, just not as popular. Codeberg: Completely open source (I believe) it’s the option with most respect for your privacy. Lacks the network effect until fediverse integration is complete, which I do believe the platform is working on. Cgit: A very simple git repository viewer. You can’t do anything from it, except see the repository. Some big projects use this, like the kernel.
There are more options, but some gets very specific after this.
