I've just signed up for the service myself to check it out, and at first glance I am not impressed. Librify was supposed to be built around the idea of creating a virtual book club-type experience, but from what I can tell all of its social aspects require Facebook integration so you can see what your existing Facebook friends are reading in the Librify app.
Speaking of which, this 18 month old startup has an iPad app but no app for iPhone or Android.
And the iPad app is unable to access the ebook I bought, so it's not doing me much good either at the moment.
Since all of the social aspects seem to require Facebook, I'm not sure why someone would need Librify as opposed to joining a book group on Facebook or Goodreads. On the latter site you can find millions of like-minded readers, and you can also integrate your Kindle account.
The prices in the bookstore don't justify joining. I got a very nice discount on the monthly free ebook for September, but the prices in the rest of the store are unremarkable. I spot checked a dozen titles and found that the Kindle Store had about the same price on eleven titles, and a slightly higher price on one.
To be fair, I've only looked at the service for a couple hours, and that's really not enough time to form a real opinion. Instead, ask me again in a couple months. I plan to hang around for at least that long, and possibly longer. (At the very least I need to give Librify that chance to fix the iPad app.)
I can't speak for other readers, but I plan to use Librify to step outside of my safe zone for reading materials. I'm comfortable reading mainly a limited set of authors and genres, but over the past year I have been experimenting a little. I've bought bundles right and left in the hopes of finding something new and readable (results: oy, vey), and now I plan to see if Librify can fill a similar need.