First, if you're in the AEC industry, big enough to need Vault, and still using basic AutoCAD, then you will have major problems in the next few years that neither subscription perks nor enterprise data management can really help you with.
Second, I've used Vault for several small pilot projects and I've found it to be very stable once you adjust your processes to compensate for the unintuitive folder structures it creates. I never pushed the MSDE/SQL Express version past 3 users, but the SQL Enterprise version is the real thing. The biggest issue is education of your staff, followed by IT tricks to lock down as much as possible on the local machine.
Third, your question about CDs is a good one, because Vault for C3D and ACAD currently lacks anything ressembling a publishing interface. With a little sleight it's possible to make sheet sets work, but it's a source of constant pain. This, in my mind, is issue #1 that needs to be dealt with.
All that said, I think Vault is by far the best integrated drawing management solution out there. I think it is right now immediately useful to most AEC companies, and once it incorporates publishing it will be a no-brainer.