One issue with the Android phones (tablets) is that there is no assurance that your brand new device will be able to run the next version of Android (or even the current one) not even if the vendor promises you that it will.
The current version is called "Jelly Bean" and was first released in July, 2012 as Android 4.1. After updates - 4.1.1, 4.1.2, and 4.3 - less than half of Android devices run "Jelly Bean" and only 1.5% of them run the latest version, 4.3, which was released in late July, 2013.
Android users don't update because they don't want the new features; the manufacturers and carriers do not make the update available. So much for being in control.
On the other hand, in less than one week after its introduction, more than 50% of all iOS devices had updated to the latest version, which is compatible back to iPhones released in 2010.
Tom