I like the idea of a cloud-backed IDE that has an Offline/Cache mode, but is it even possible to provide the non-editor part of the dev environment (things like the terminal and all of the associated state in the container) while offline when they live on the server? That non-editor part of the dev environment is really the main appeal of a cloud-backed IDE for me.

Also, I have yet to find a cloud IDE that has proper support for building iOS apps. Sure you can delegate the builds to some external build service, but sometimes you do need the flexibility of a local build environment for advanced debugging and working around certain issues.