not sure if it's been mentioned but I've noticed that the mobile app (I use an iPhone) tends to freeze and becomes unlock-able, and unusable if I'm logging in and periodically lose reception or access to the wifi network.
an error messages appears stating "error: connection timed out" or something similar, and then the screen remains blank and black. nothing at this point, save turning my phone off and back on, allows the app to restore; even once strong reception or wifi access is restored.
not exactly life threatening but annoying nonetheless when I'm using the app outside of my home wifi.
whadup, we got JUICE