Have you got much traction on this so far? I've only run a handful of events, but in some cases the event location provided the audio hardware for free, and it was already connected into their systems. In others it was important to us to have professional looking microphones - talking into a mobile phone would kill that visual impact / user experience. In a group situation, passing a wireless microphone around also has the benefit of indicating who has permission to talk.
I guess I don't really understand the value proposition here (beyond encouraging all your attendees to download the app so you can get their personal data via the social media logins).
