You can compare this download to you downloading this 1GB file from a webpage. And I would say web browser will handle it much better with memory usage etc. Python propably does a poor job there with that big of files with the standard httplib that is basically for getting web pages, not 1GB data files. In theory the download should work but probably get into trouble with the mobile devices memory or something.

If you do any change to a file it will be fetched again completely, there is no way for me to know what bits to update etc the dropbox desktop clients get the whole file also not just updated "parts". At least this is what I assume and have noticed when using the clients.

With the current API and things I am working with it's hard to make a client like you see on the PC that does networking for big files etc. perfectly. This client is for most use cases but not propably for getting 1GB files daily. You will find better luck most likely by using the dropbox.com web interface to fetch your big files than my python client