I built and iOS library for this last night (i'll open-source it soon). I love this idea and for iOS apps that don't have a web backend, this is a great and easy way to implement CRM with your app user info.

We use TestFlight a lot in our iOS apps. TestFlight is great for tracking what your users are doing inside your app, and logging errors. LessNeglect goes a step further and lets you tie users and actions together with an open communication channel.

I'm going to use this specifically to allow users of my iOS apps to send me support requests, and to also track in-app purchases.