So can I eventually drill down to something similar to the Win Explorer directory/file tree?
Yes, with enhancements. It's actually a minor improvement over what I had in XP/Vista if I recall correctly
For instance, under the "View" menu you have a toolbar that
- has several choices of icon sizes. So on a high-res screen I need medium icons or larger to see what Dropbox is doing. For choosing photos I might need large or extra large. But if I only hover over the choice it gives me a preview so I don't actually need to change the setting, just hover for a second
- it has a Group By function so I can group by file type and then sort alphabetically, for example
- I think this has existed since Vista (not in XP though) - when looking in the address bar for file location, hover over any folder in the path and it gives you all subfolders, so you don't need to locate yourself in the folder list or navigate back up through the tree.
Several minor UI improvements like that when I have to go back to an XP machine (and if you have a need to test IE8, which I do lately, you need access to an XP machine, whether physical or VM).