Id say they are probably about the same security wise, with iOS and Android having better security in different areas (for example arbitrary file write in iOS i

Id say they are probably about the same security wise, with iOS and Android having better security in different areas (for example arbitrary file write in iOS in an end user application generally doesn't results in RCE but it can in Android). The old thought that open source is more secure doesn't seem to really hold as there are terrible bugs in nearly everything all the time. It should also be noted that Apple is rewriting certain parts of iOS in safer languages as well (see blastdoor for messages as an example).