For what it's worth I'd say that Android AV is pretty much useless, but you absolutely should have security software. Just make sure it has good anti-theft, data recovery and tracking components. The trouble with Android AV is that the threat is less likely to come from a drive-by install, and more likely to come from your installing a legit or semi-legit app. Or, indeed, your device being lost or stolen. So you need to be able to track and brick a lost device, and recover data from it.

I wrote a thing about this just the other day: http://www.pcadvisor.co.uk/how-to/security/3400697/how-manage-threat-your-smartphone/