I have been using the PDF conversion tools by Nitro PDF to convert PDF files back to Word or Excel format for quite some times. The result of conversion is pretty satisfactory.
They provide free conversion service, whereby we can submit the PDF file to them via their website, and they will email to us the converted Word or Excel file. The major limitations of this free conversion service are: can only submit 1 file at a time, and there is a submitted file size limit of 10MB only.
Anyhow, they also sell the Nitro Pro standalone conversion software that can be installed in your PC and perform local conversion without going through the Internet. Batch conversion is possible with Nitro Pro, and the file size limit is eliminated as well.