It would be great if Adobe themselves came back with another in-house option, if they planned to do so I wish they'd left the service up and running until they had a new offering... I know we all had advanced warning but like most things I waited until it was gone before worrying about it (guess I thought it would be easier to configure).
The issue I've run into with WebDav (at least with SqueakSoft) is I have to provide my admin username/password to reviewers in order for them to open a file, although they say the are working on a "sub-user" option that will be available in a few weeks time.
I'm on a Mac running the latest OS so SharePoint is not an option for me, DropBox sounds interesting but i'm not sure I want or need another monthly payment.