The recent WWDC conference highlighted the edge the iOS has over its rival in the OS conversion rate. The android is lagging behind in ensuring its users to shift to the latest OS. These disparities affect both users and developers.
Developers : A wider target
Developing the softwares for android means a lot more resources, as they have to cover more than one version at the same time for a wider reach. Though developers still support earlier versions of iOS, the new applications might target the newer versions as they can cover almost 90% of the users through this approach.
Users : Left behind and sometimes confused
Users at the other end might have to wait for some flagship applications for a launch on Android platform. This might not be the case now as many applications are also Android first. But the real confusion among the users will be the upgrading to the latest OS. The carriers and device manufacturers usually delay the upgrades as they take time to come up with their version of new android version. The users are left to fend themselves until the official release occurs(sometimes there is a delay of more than a month for the official version of OS to release). Though this might not be the case with devices having Vanilla android version.
Read about Vanilla android here