I am just starting to use this, having discovered it via the suggestions in the app store.
I have no idea how they are providing this service without any apparent way to do an in app purchase however this is a much better experience than looking at your rss feeds in something like Flipboard.
Curated suggestions, top charts, excellent sources, what more could you ask for. I will go back and update this review if it turns out that the emperor has no clothes, however so far this is just what I was looking for.
In addition, no need to download the articles to read later, because it is downloading them all for you.
JeffDBoston about Longform: A Smart Reader