I am a salesman and would like to use my new iPad professionally. I need to be able to open PDF's and Excell files quickly as my customer visits are short. Also these files should be synchronized from my PC at home and be available with no wifi or 3G connectivity. I have tried DocstoGo, but find it lacking in speed, it just takes to long to load a pdf page.... Any recommendations as to an app who could suit my needs? Thanks in advance!