Due to the need of reliable integration of all sub-systems like gyro, isonometer, ambiance light sensor, and other critical components; at this moment there is no other system that is reliable to do the job except iPhone 4 / 4s with the Apple iOS.
To perfectly mount iPhone 4/4s in the bracket with +/- 0.003" every time, We assume that the only thing on the iPhone 4/4s that is made extremely precise is the stainless frame which is +/- 0.001". So if we add a rain/vibration cover, we are not sure about the accuracy and there are many different sizes and shapes of waterproof case on the market which is virtually impossible to make a bracket which will fit all the cases with high accuracy.
It is always a good idea to put iPhone in Airplane mode when using iBowSight. As when the phone rings, the dominant App will be the phone App, until one puts it in background and put iBowSight back as the foremost App. Otherwise, the iBowSight App will be sent to back and cannot be seen. It will be devastating when one is pulling back and aiming at a deer and suddenly the phone rings. Regarding text message, they will only roll on the very top of the screen which will have no effect to the operation of iBowSight when one is receiving text, even when it is not in Airplane mode. Below shown what happen when iBowSight is the Foremost App when a text message was received.