If you happen to have critical virtual machines or disk images, make sure you back them up elsewhere, since Backblaze doesn't back them up. Made it an annoyance for me personally, but it otherwise works rather well for the typical user.

Backblaze backs up my virtual machines... You just have to remove those file types from the exclusion list (where they are by default), and raise the max file size to "No Limit". Neither of these are hidden options.