I tried to do a complete OneDrive backup of a modest (23 Gb) account (Windows 10 OS). I checked the photo directory and found that IDrive had failed to upload large portions of it even after three days. In fact all progress appears to have been made in one day.
What's worse is that IDrive gives no indication that the folders that appear to be successfully uploaded are missing files. One folder is missing 50 files of 1,046. Another is missing 6 of 1,186.
Some of my other folders, the larger ones, do not upload at all.
When I manually select these OneDrive folders to upload, the IDrive screen (on Chrome) freezes and hangs. A small number of files get uploaded and then no further progress is made.
My main reason for trying IDrive was the direct OneDrive upload, but clearly I cannot trust it to work.