As a first time attendee at this conference, I found the app extremely helpful.
Personally, I will bring a tablet next time. A little easier to read than on a phone (old eyes).
My suggestion for improvement has to do with the messaging feature. I was not able to find a way to have the option of deleting messages after I read them. That feature would be helpful, especially when messaging with colleagues.
The ability to see slides and make notes on those slides was very helpful.