For a 3-mon system managing 25TB of data, I think explorer is what you'll use. I'll be shocked if there isn't a way to make explorer your default. If there isn't at lauch, someone will fix it.
They may also have difficulty getting large companies to upgrade unless the Metro UI is easy to disable. Lots of companies are still on XP because they considered 7 such a dramatic change; I'd guess that a forced major change to the entire UI could spell disaster for their Enterprise sales.
