With my iPad 3 I use CloudOn for Excel, Word and Powerpoint work. This app provides cloud-based (Box, Dropbox, Google Drive, Skydrive) access to your files, and provides a touch-based interface to the Office apps. Yes, you can play games and everything else you mention - but it's also an excellent productivity device when used with a wireless external keyboard. I'm not dissing the Surface Pro, but the iPad most certainly isn't "just a fun screen with a lot of games." Aside from running full blown Windows apps, the iPad can pretty much do anything you want with cloud storage.
And Microsoft is still quite lacking with modern UI apps, but hopefully this will change soon.
All of this said, I'm still considering the Surface Pro because I like the direction Microsoft is heading. Having basically a desktop PC in tablet form is something of an achievement. Yes this design will improve, especially with Haswell coming later this year, but I believe the Surface Pro is currently the best tablet-based Ultrabook type device available.