Re: if I'd start a new company
"...I would use LibreOffice and set up an OwnCloud server for sharing documents. That way, I would save $$$ and keep control over my own data."
Depends if you need to run business applications like macros, addins, etc. and to exchange documents with other companies, have centralised group policies, etc. If you are 1 man in a van Libre Office is probably mostly bearable. As soon as you need a proper enterprise grade solution the list of inadequacies is exceedingly large. Don't forget that licensing is usually only a small part of software TCO!
Biting the hand that feeds IT
