For consumers, and most small businesses, the choice comes down to using a Local profile that only exists on that one PC, or logging in with a Microsoft ID, which syncs settings and passwords between different Windows 8 systems, and opens up access to a range of apps and features that aren’t available with a Local profile. I think you can tell from the wording of that comparison which one I prefer.
For a business using Surface Pro tablets (or Windows 8 in general) connected to a network domain, things are a little trickier. By default, connecting Windows 8 to a network domain blocks the ability to access the apps and features that require a Microsoft ID. Microsoft had the forethought to realize that IT admins probably don’t want users installing Windows 8 apps on their own, or managing email, contacts, or calendar events outside of the prescribed business tools.
But, it can be done. The option is there for an IT admin to allow the Microsoft ID access to live in harmony with the network domain access, so a user can engage in both business and personal activity–especially beneficial for BYOD scenarios (especially if the Surface Pro is actually owned by the user, but you want to connect it to a network domain for work purposes).
Take a look at Surface Pro, Day 3: Logging in to Windows 8 for more on my experience.