I haven’t downloaded any iPad productivity apps yet, but if the assertions below are accurate, it’s not clear I’d benefit from doing so; email is not a robust file storage option. I was also disappointed to discover that the Office Web Apps (e.g., in conjunction with Skydrive) can’t be used on the iPad at this point, although they work fine in Firefox and Chrome (as well as IE, of course) -- “think different…”
Pages, Numbers, and Keynote are fairly good applications on the iPad--though you have to pay $10 each for them. Unfortunately, the iPad offers no local storage, so moving documents around is a real pain. Basically you have to e-mail them to yourself and open them from the Mail program or from your favorite Web mail client, and then e-mail them back when you're done (you can mail documents from within the iWork apps). Many features within Excel and Word (such as macros and drop-down boxes) won't work properly, either. The on-screen keyboard is good enough for hunting and pecking, but taking lengthy notes or writing long papers or articles is a chore: You can't really touch-type on the new keyboard. A number of iPad-compatible productivity apps are available, and things like Evernote work great; but if you want to get any real work done, this is not the device for it. Though you can sync with Exchange, the Mail, Contacts, and Calendar apps are missing features that business users rely on.