While researching productivity apps, I have found many articles about Dropbox (https://www.dropbox.com/) and Evernote (http://evernote.com/), and many people seem to like both. These services are based in the cloud, and I think that both services are good productivity apps. If you are wondering about the differences, you may find the following articles below interesting. However, I have also discovered that you may be restricted in use to one or another if you combine with another app or a device. For example, when I was testing a Livescribe Sky Pen (http://www.livescribe.com/en-us/smartpen/wifi-smartpen/), the Sky pen model only supports Evernote app. A text-to-speech app, Voice Dream (http://www.voicedream.com/), uses Dropbox.
Dropbox vs Evernote – The Differences Explained, and How to Use Them Both Effectively
Evernote and Dropbox Why
I Use (and Love) Both