Is it installable using vanilla-esque yum or apt?
It's intentionally different than UNIX shells. If you are expecting UNIX shell behavior you will not like it.
I have to use it at work for Windows stuff. It is amazing. But I would never install it on my home computer because I don't trust all the other Microsoft stuff that comes along with it.
There is one big complaint that I do have with it - working with massive (multiple gigabyte) files is a pain. It wants to load the entire file before doing anything; most likely because it wants to treat everything as an object - therefore it has to build the objects before it can work with them.
Can it finally manage Office 365 and the like from Linux?
I tried it once (1-2 years ago) to run some command that couldn't be done from the web interface. The docs said, "this should work". As I expected, it didn't. Some further digging turned up that it didn't support OAuth2 or something related to authentication.