bill - 4:24 am on Jul 26, 2013 (gmt 0) [edited by: bill at 8:48 am (utc) on Jul 26, 2013]
I believe he is referring to compatibility issues. If your customers are using Microsoft Office and you edit spreadsheets with macros, complex formulas, or embedded objects, Word docs with complex formatting (using footnotes, references, etc., or even just headers/footers), or almost any Access database or PowerPoint presentation, with LibreOffice you're in for trouble. It depends on the versions used, but you're almost guaranteed to mess up the files.
As far as functionality goes, LibreOffice and the like are fine features-wise. If you and the people you're working with are all using LibreOffice there's no problem. It's when you start moving between platforms that the issues generally arise.
[edited by: bill at 8:48 am (utc) on Jul 26, 2013]