Microsoft this week released two public previews of upcoming low-end Windows Servers, one aimed at homes and home businesses, and the other at small businesses. For those very small businesses that previously found managed servers to be too complex and expensive, these products—Windows Home Server "Vail" and Windows Small Business Server "Aurora", respectively—represent an interesting and perhaps unprecedented conundrum: they're both excellent, and it's unclear which is the better fit.

Vail is the next-generation version of Microsoft's Windows Home Server (WHS) product, and like its predecessor, it offers excellent media sharing capabilities. Vail also includes a new version of the Drive Extender technologies, which lets users add internal and external hard drives at any time, without needing to worry about drive letters, partitioning, or other configurations. With WHS, all storage is aggregated into a single, easy-to-use pool. Drive Extender also provides seamless data duplication functionality, so that all files are duplicated on two different physical disks, to help offset any hardware disasters.

While Vail is aimed primarily at home users, it offers some interesting benefits for small businesses too, including the centralized, pooled storage, centralized PC backup and recovery, and remote access functionality. And because Vail servers will be inexpensive and easily upgradeable, they're a great addition to almost any environment.

What Vail lacks, however, is compatibility with Active Directory-based domains. And that's where Aurora comes in. Small Business Server (SBS) Aurora looks and works almost exactly like Vail—it even features the same add-on extensibility model—but with two major differences. First, an Aurora server is a domain controller, and all of the users, computers, and other objects you manage from this machine will be part of a real AD domain. Second, while Aurora does include the excellent Drive Extender capabilities of Vail, it lacks the media sharing functionality.

So Aurora may seem like the obvious choice for most small businesses. And that's true, except for one wrinkle: Aurora can't be added to existing domains. If you go the Aurora route, you can do so only for new domains. Vail, which operates outside of domain management, is in this way a better choice for in-place, departmental storage, as well as those smallest of small businesses.

Either way, you can't really lose. I've been testing both Vail and Aurora for the past few months and am looking forward to the final release of each. In fact, I'm thinking about switching my own home environment over to both products, using Aurora for user, security, computer, and document management, and Vail for media sharing. The thing is, they're so good, I'm not sure I can choose between them either.

I've written a bit about both products on the SuperSite for Windows, but the two most pertinent articles are the Windows Home Server "Vail" Preview and my overview of the Windows Small Business Server "Aurora" Release Candidate.

If you're interested in testing these products for yourself, they're both available on the Microsoft Connect website. You'll need to sign-in with a Windows Live ID and then visit the Windows Home Server and Small Business Server pages to access the pre-release code.