Please all, and you will please none.
What do we want out of a mobile app for our event?
- Feedback (surveys)
- Engagement with content or people (QR codes, connections, check-ins)
- Maps of venues
- Agendas, especially if they are personalized
- Notifications from partners or updates to agendas
- Partner content
- To work on iPhone, Android and Win 7 phones
I haven't found any off-the-shelf solutions to meet all of these needs, but have worked with some custom design companies to get us what we want. With mixed results.
My recommendation is: Choose your vendor well.
Vet their personality as a company - are they willing to work insane hours to meet your goals? Are they willing to partner with you to allow your event to shine? Are they willing to be onsite to help if anything goes wrong? Do they intend to work with you again, and will they support you throughout the build and implementation process to ensure you want to work with them? Have they ever gotten apps approved through the four majors marketplaces (iPhone, Android, Windows, Blackberry)? How many have they done? Can they code in such a way that even after the app is approved and in the marketplaces, a few tweaks can still be made?
Be careful as you get into mobile app development for your events to determine why you are doing and what you hope to gain. Apps are awesome and they are fun and they are cool, but usage rates are still relatively low for the majority of event participants. Some have corporate phones that prevent them downloading apps. Some are on Blackberry and can't get any cool features. Some prefer paper. Some just prefer to save their battery for more important things.
To do an app right, you need to have amazing content. If your intent is to meet the minimum requirements of app-coolness, pick an agency that will load in your agenda for you. If you actually plan to have loads of cool info in the app, ensure that you have the internal resources to gather, edit, and manage the inclusion of the killer content.
Have a plan for the future. The first thing I do after an event is usually remove the app from my phone. That's 3MB-6MB my phone doesn't need on it! So if you expect me to keep your app on my phone, tell me why and then make sure it's something I want to keep. Just about all the conferences I've been to in the last 2 years have changed app vendors year over year, making me download the new app anyway.
Perhaps there are other methods you could pursue - like leveraging LinkedIn or Facebook. Or perhaps going with an event social network like a Vivastream or SocialGo.
So when it comes to signing up for an event mobile app: think before you ink! :-)