Neevia is interesting for a few reasons. You access your converted files on the Webpage or receive them via email. It also offers multiple PDF formats as well as the option to put watermark and encryption on the PDF, which are all easily achieved through the main interface.
On the limitation side, Neevia has a 1-MB file size upload limitation.
Our test Magna Carta document converted quickly and without incident using this service. The Excel test file, however, did not, as Neevia did not correctly format to landscape to get the proper width of the spreadsheet.