Metadata gets a lot of bad press. Whenever it's mentioned, someone is getting blistered by hidden data they negligently left in an electronic file.
Metadata is actually a functional and necessary element of files managed by a computer operating system. A computer tags each file with indexable snippets of information such as the file's creation date and author so that the operating system can properly identify and catalog the file among thousands.
First, a PDF will look exactly the way you intended as long as your recipient has at least the free Adobe Reader . If you send a Word document, you may have created the document in Word 2007, but your recipient may still be living with Word 2003. There shouldn't be any problem viewing the document, but different versions can sometimes clash and misinterpret formatting preferences.
Next, a PDF is hard to edit or modify. Obviously, this isn't helpful when you intend to collaborate on a document, but if you are sending a finalized draft to opposing counsel or an external customer, you should always convert a Word document to PDF (which can be done through a full version of Adobe Acrobat or one of the many other applications that will "print" PDFs).