Hi,
The programming for this app should be pretty straightforward depending on the protocols and APIs you have for those products, but one of the most important factors for this app to be successful should be the way it's designed and the way the user interacts with it.
If the users don't like the app, it usually doesn't matter how well programmed it is, but their first impression of the app.
Have that in consideration when choosing, whoever you choose.
Cheers,
João Esquimó