Unlike the Sun approach, WinFS is a database-driven storage subsystem that isnt a file system itself. Instead, WinFS is designed to work with the existing NTFS file system model (as well as future file systems from Microsoft). Its designed to store all sorts of data, structured and unstructured, or anything in between.
While WinFS can store meta-data, it is not explicitly a meta-data store. If anything, WinFS is an item store. And each item is carefully defined so that it can be retrieved.
At the same time, items need not have a file association, just a definition. Common definitions could be items such as contacts, messages and images. If a item type needed doesnt exist, developers can create a new type from an existing type or created from scratch using the API set.
In addition, WinFS isnt concerned with managing the available physical or virtual storage, rather, it provides services for managing monitoring and manipulating the items of which it is aware.
For Suns customers, DFS will provide major advantages to system administrators responsible for storage management in the Solaris environment.
In contrast, the primary advantages of WinFS will be realized by the end users of the operating system, allowing them to store and access data in a less-structured and more-comfortable fashion.
While application developers will be able to take advantage of the APIs that support WinFS and find new and easier ways to share data, it is the end-user that will see the greatest benefit from what WinFS brings to the future Microsoft operating systems.
The storage advancements from Sun and Microsoft in large part reflect their different customer base: Sun is focused on making the OS more usable for the enterprise administrator, which will then trickle down to the end-user. Microsoft focuses on improving the user experience with technology that will allow more advanced applications.
Actually, these are complementary strategies, though I doubt you could get anyone at either company to agree to that even with their recent public détente.