The app has a 45 sec - 2 min lag when logging in and when switching from market view to your orders or portfolio. A lot of times my phone will go to sleep while I'm waiting to log in. This will cost you money and you will miss trades. I also don't think it's necessary to require authentication every time the app loses focus. So if I go look at another app when making my trade decision I now have to log in and I could have trouble logging in waiting several minutes to make my trade.