I recently purchased a surface as it was reduced and I've been wanting to try one out for a while.
The device is really good I'm really impressed, however the apps are a bit poor. It's not so much the number it's sometimes the quality, for example I used evernote a lot. The worst version has to be the touch one, the iOS, Android and desktop apps are much more advanced. I know this is down to the individual developers but that doesn't change end users experiences.
Like I said I really love the surface, it's a work horse and handles anything thrown at it, I would love to see some more big name apps on the store and for some of the existing apps to improve in quality
DropBox - needs massive improvements, basically just the web page in an app missing loads of functionality and an offline mode.
SkyDrive - needs a sync to local folder/local SD card
Evernote - needs to be on par with the iPad and Android tablet equivalents
1Password needs to hurry up and get an app going.