They have a list of costumers but I really don't know of any large-scale implementation.
I've been testing it on my notebook and its compatibility with OOXML is much better than LO. Of course, harder cases break on both. So, even combining both, something I've tried to do, is not enough to achieve good compatility with MSO.
I've been testing it on my notebook and its compatibility with OOXML is much better than LO. Of course, harder cases break on both. So, even combining both, something I've tried to do, is not enough to achieve good compatility with MSO.