Some interesting anecdotes and attitudes in a thread on Slashdot that started yesterday afternoon and has 463 comments already …
"Looking through an article on the smartphone office suite Quickoffice, I noted a claim by a company executive that OpenOffice users usually save their documents in a Microsoft format, e.g. .doc. Hence the company has no plans to support .odf. I guess I can see the rationale for this — it helps if you're sending a document to an MS-using company — but what's this community's general experience of saving in .odf vs. .doc format?"
I think that all the comments tell you is what type of person reads slashdot. They certainly aren't representative of the average PC user.