touch panels have there advantages listed above, but iPads work well if done correctly.

If possible have dedicated iPads for control and have a separate iTunes account for control iPads. This way you can have access to do everything without having clients personal info. Also turn off all notifications for everything and sign out of iCloud. Use Launch Port sleeves and base stations for charging. Have iPad for each room so jumping between AP's is not an issue (iPad Mini, launch port sleeve and base station are approximately $700 per room)

Biggest draw backs: have to press home button twice to open (as long as Crestron app is always open), iOS updates, older iPads no longer support new iOS (but new iPads don't cost much more than replacement batteries for touch panels)

I usually use touch panels for in wall use, and iPads for wireless use. I have close to 100 iPads in the field for Crestron control and if done correctly they work well.