All I can say is that I've been using Android for well over a decade now, and not once have I seen malware that hijacked volume buttons. It might actually be a permission the app has to request - I don't remember.

Either way, this was meant as an illustration of how small factors can affect decisions. I have had an iPhone as my primary phone for a few months, and this one thing was the single biggest issue I had with it at the end of the day - not that there weren't others, and some were actually more annoying when they happen, but this one is at the top because it's something that's constantly in my face. Thus, I'm not going to buy another iPhone for this reason alone; my response to "you're holding it wrong" is "you're making them wrong".