ZumoDrive launches Palm webOS and Google Android clients (opens in new tab)

Probably a bit of both. Seeing as WebOS is based on the HTML/JS model that web applications are already familiar with, it might have been more obvious to them how to make it look fancy. With Android, you have to start diving into how the layout and widget systems work, and requires working with Java and XML, but it is indeed possible to make things look just as nice.

Not really.

ZumoDrive doesn't use space on your drive for it's storage. It simulates a network drive as far as your OS is concerned.

Dropbox actually uses space on your drive , and syncs that across your machines.

So , ignoring local caching done by ZumoDrive , we could think of it being network intensive , whereas Dropbox is space intensive.

(I could be wrong and would love clarification. Also, 'intensive' is probably not the word I'm looking for , but I can't come up with a better one now)