I played around in the past with the three proposed tools. I start my overview with the one I know the least.
I tried out paper.li back in 2011. This tool seemed to be much less complicated at that time. I connected with a twitter account and the tool automatically made an online “newspaper” based on the twitter timeline. It is still working today and it still has an amazing content.
I considered paper.li more as a discovery tool, especially because I didn’t visit twitter very often. Nowadays it is also possible to add content from websites (rss), facebook, youtube, etc. So you can really can make a paper covering all your interests from different sources.
Also in 2011 I considered the functionality of scoop.it less interesting for me than the one of storify. But looking back on my scoop.it stuff of that period, I think it is funny and powerful. I’ll keep it in mind for later use.
Storify is very handy to curate tweets, but not only that. You can following “events” with relevant youtube videos, articles from websites etc. I even used some of “my storifies” to embed them in a blog post.