SharePoint 2013 Mobile Apps

I’m currently writing an article about building SharePoint 2013 mobile apps and things to take into consideration or think about before you begin.

I’d love input from my fellow community members, so if you have the time to answer 1 or more of the following questions, I’d greatly appreciate it!  Please specify which question number you are answering.

1. What are your favorite new mobile features that were introduced in SharePoint 2013, and why?
2. Does your company or any of your clients currently use any 3rd party or open source mobile solutions?  If so, which one(s) and what benefit do they provide or what problem do they solve?
3. Do you think it’s better to build mobile apps for SharePoint, or just create a mobile browser version of your SharePoint site that works in all the major mobile browsers?
4. How concerned is your company (or clients) about security surrounding mobile apps, such as, sensitive SharePoint documents falling into the wrong hands via mobile access; and what do you recommend they do to keep their content secure?
5. Are there any other things your company or clients should consider before they start building mobile SharePoint apps?