There is no direct comparison, so unfair to call them slower or worse. Both these services are for running your own private server and for browser IDEs to be thin clients. You can configure the server with your language tooling, build scripts and whatever else. You can also pause and resume your session from a different device (since a majority of business logic is handled by the server).
vscode.dev runs fully in your web browser, and files are read from local disk. There is nothing in the cloud. So yes it is faster, but serves a different use case.
Geoff from Gitpod here. GitHub, GitLab and BitBucket are 1st class citizens. In time I’d like to see Gitpod extend support for sourcehut, cgit, gogs and gitea but we haven’t got around to it yet. Fortunately Gitpod is indeed opensource so anyone in the community could send in a pull-request and add support for the context parser. Come join the discord at https://www.gitpod.io/chat #contributing channel.
https://github.com/gitpod-io/openvscode-server
https://github.com/cdr/code-server
Update: also check the discussion about their differences https://github.com/cdr/code-server/discussions/4267 (IMO both are much slower and worse than vscode.dev)