Kram3650
- Github Codespaces are pure IDE hosted environments to run VS Code, Visual Studio etc. They are using linux docker containers underneath and fully hosted by GitHub
- Cloud PCs (Windows 365 or Dev Box) are meant to be SaaS like VDI. Low complexity, less options - biggest Cloud PC is currently 8 vCPU, 32 GiB Memory. They both run off AVD behind the scenes. W365 is licence based, Dev Box uses normal Azure VM consumption costs. So a dev box can run full UI-based apps, anything that runs on Windows (or Subsystem for Linux)
- AVD is fully customisable from the VM size so if it is available in that region you can use it (think mega RAM, GPU-based VMs). With the extra flexibility comes extra management and governance needs
So they can all be used for different reasons and I wouldn't be surprised if a developer in a large multi-org enterprise had a normal basic corp laptop with access to a W365 Cloud PC, a couple of different Dev Box environments and maybe AVD where relevant, while using Codespaces when wanting a quick IDE anytime they are in GitHub!