Where in this article are you reading that you shouldn’t use either of those services? The only thing I can think of is that maybe you’re reading the list of advisory links without clicking through—but by that logic we also would then eliminate Dropbox. The Box.com “advisory” in particular was always a bit of a joke. They said their service couldn’t handle syncing folders of files (in essence, they said “packages” but probably this was written by someone that didn’t know that a package is just a folder) for a few years, then finally fixed it.
Please carry on any further discussion of whether or not X, Y or Z is safe to use, in one of the existing threads: