Google chairman Eric Schmidt says in the Gartner Symposium/ITxpo that Android is more secure than the iPhone despite the fragmented way of its different devices does updates. He didn’t really elaborate, just pointed out how many Android devices are activated and how apps go through rigorous testing. More information here: http://www.theverge.com/2013/10/7/4814422/eric-schmidt-says-android-is-more-secure-than-iphone
Personally, I can’t gauge the security of Android for most devices but I am not really having problems with my own phone. I have an antivirus although I don’t really see the need to use it obsessively unlike with my PC. How about you?