Late last month a number of UK banking apps had some "glitches." You can read how the BBC reported it at http://www.bbc.co.uk/news/business-26387754
I think there are 2 things we can learn from (or be reminded of by) this incident.
- People assume the problem is with an app, even if it's the server/services that the app uses. They don't see a difference. You need to think about the experiences you create in a holistic sense.
- Test your back-end systems can cope with the load generated from lots of people using your app at the same time.