It's great when it works,
I sell digital products with large file sizes (average 3GB) and my uploads get interrupted about 70% of the time, the option to sync to dropbox or google drive for reliable uploads would be a great addition to the shopify digital downloads app.
otherwise this is a GREAT app, there are a lot of paid apps out there but are very limited when it comes to file size and storage space and they are very expensive. as far as I know, this app has unlimited storage which is pretty amazing in itself, plus its free! (I would pay for this)
note/tip to users running Adobe CC: if you are uploading large files and get cut off, try disabling or lowering its upload speed, it pings the Adobe server at random times which can cut your uploads to shopify really quickly.