#4: The OpenACS 4 file-storage package gives you the option of having the files stored in the DB or filesystem. It's a package-level parameter meaning you can change it for each new instance. You can thank Jowell Sabino for this enhancment. I'm slowly moving all packages that allow the uploading of files in this direction, and will add a system-wide default parameter in our second release cycle. ACS 4.2 Classic stores files in the DB.
#1. See #4. It also has a shitty UI in comparision to 3.2.5. Fixing that is part of Open Force's task list for dotLRN.
#2. Yes. It uses the standard [Open]ACS 4 permissioning system, which is slightly more flexible than the 3.x model.
