The web versions of MS Office tools are actually pretty well build and feel pretty close to their desktop counterparts.
If you have to write papers with a lot of math in them libreoffice's equation editor is way better anyway. It rarely crashes and uses it's own simple markup language instead of the finicky WYSIWYG editor in word.
1. Word - track changes 2. PowerPoint - equation editor
As for the formatting - yeah, MS doesn't seem to follow its own document formatting standards, even for the newer documents. That puts other suites in a hard spot: a) follow standards and present imperfect documents, or b) invest immense resources into bug-for-bug compatibility?
I don't know Excel but I know there are people running entire departments on Excel spreadsheets.
(Having seen many Excel spreadsheets, 80% of the work is done by rudimentary means: pivot tables are Advanced Magic in this regard)
You can edit the markdown in vim which IMO is mentally easier to write prose in because you're not distracted with all the formatting and spelling. You use aspell for spell check and pandoc/pdflatex for typsetting.
It should be able to handle most use cases
My anecdote: I was about to have an important meeting and needed to print off some sheets from my Windows-based netbook. The power was low (<3%), so I plugged in the charger and resumed it from hibernation. It had been offline for a little while up until then because of traveling. Seeing the power was plugged in and I was shutting the machine down going into the meeting, Windows presumed that right then was a perfect moment to perform a Windows update. That night I wiped it and put Ubuntu on there.
FYI the Linux experience has been mostly great. There's been maybe a problem once a year, with some driver or package issue - but most of the time it runs great. I can safely run anything on it overnight knowing that it won't decide to do anything on it's own accord.