If you really want to convert PDF files to Kindle format, first subscribe here to Adobe Export for $ 20.00 per year:
http://success.adobe.com/en/na/sem/s...S|e|9201585503
Then send your resulting Word file after your own editing to your Kindle using the email address on the Manage Your Kindle page at Amazon.
That will give you a perfect Kindle file allowing Kindle fonts, highlighting, notes, bookmarks, etc.
From that Adobe page:
"Adobe ExportPDF makes the most of richly formatted PDF files with the ability to preserve paragraphs, tables, images, and even multi-column text."
I just made a copy of this post myself in MS OneNote just in case I have to do the same thing with a really necessary PDF file.