Document Management solutions that work with Macs?

Hey all, Our foundation is currently examining different document management solutions, and while all our client computers are Macs, most of the document management solutions out there are Windows-centric (think SharePoint, Documentum, even stuff like box.net sync is only for Windows). Has anyone out there encountered a good solution that allows for versions, version comments, and offline access that plays nicely with the Mac? Thanks, Jason