At my work most dumped their Android phones for iPhones because Android didn’t support CalDAV natively and third party solutions were wonky at best. The only lag I see on iPhone 4 with iOS 6 is bouncing to the home screen. Scrolling is still quite good.
Provided its a Nexus 4 or you go about hacking the device in order to get the update. New phones won’t ship with this for at least a year per history shows. Even the older Nexus devices don’t receive timely updates anymore.