This is the probably my biggest question about Steam cloud saves. I haven't messed with cloud saves much, but my understanding is that they get written to a game-specific folder deep in the Steam install directory structure. My questions:
1. If Steam goes down while you are ingame, are those files not up to date?
2. If Steam goes down, can you still play with the local copy of the save file, and then that copy will get written to the cloud once Steam comes back up?
3. Most importantly, if a save file becomes corrupted and you kept a manual backup of it, can you copy that backup file into the Steam cloud save directory and work from there, or will Steam keep redownloading the corrupted cloud save?
1. The local save should still be up to date.
2. If the local save and the one on Steam cloud don't match up it asks you which version you want to use as the correct one.
3 Because of point 2, I think that's possible, yeah.