You can download files like pdf, jpg to the device using the api's provided by RhoMobile.
You can also download the sqlite db and create a dataset from it. See http://edgedocs.rhomobile.com/api/Database
The key thing is the ability for the device to handle it. iOS and latest Android devices should handle it smoothly, however its a question on performance based on your business requirement.
Dropbox kind of app's does that.
Its best if you try out the sample app on actual devices and share your experience here.
I tried this FileTransfer and it doesn't work see http://developer.motorolasolutions.com/message/10601#10601
But this api has a filesize limit of 4Mb and i need to download file > 50 Mb
I'll checked the dropbox api.