If I could get all CVs in the modern version of Word format (>= Office 12) it would make quite a lot of tasks easier and faster.
But I can't, and since there are several Word formats and several PDF extra work has to happen anyway.
Some automated CV parsers have problems with PDFs (others can't do Word well) so that may be an issue.
However Andy and financeguy are right, PDF doesn't really protect you from anything and there are entirely legit reasons for wanting Word. As a recruiter I am concerned about firms like Resource Solutions who are part of a recruiter called Robert Walters and do "outsourced HR" for Morgan Stanley and Deutsche, and so there is inevitably data "leakage", thus we use something I developed that does undocumented things to PDF files that allows tracking, so all CVs we send to banks are in PDF regardless of the format we get them in.
However, we're really quite tough on not changing the body text of CVs because back when I had a real job, I saw how terrible that can be.
Some recruiters do you the favour of getting rid of horrible formatting or spelling errors some of which I enumerate at
TheRegister.com but of course they may get it wrong...
One thing I'd add is
please don't put (C) or other copyright bullshit on your CV. It just makes you look awkward to work with and gives no actual protection at all.
In our jurisdiction recruiters are legally forbidden from charging candidates fees and rather than say "don't trust any recruiter but me", I counsel you to think of giving your CV as like giving your credit card details and apply the same smell test since if a recruiter wants to abuse your details he can.