One problem that was constantly plaguing Android device was the process of waiting for your carrier to process and reissue the new android software update. Unless you had a Nexus device you were potentially waiting months until Sprint/Verizon/AT&T would get off their lazy ass and issue an update that contained their bloatware and a bunch of other crap.
Since getting a Nexus 7 tablet about a year ago I have loved that i receive Android updates promptly and with no bloatware. While my friends wait weeks or even months to get updates, I have them automatically pushed to my device. This is the way to go, and I am glad that Google and Samsung woke up to team the Galaxy S4 with the power of stock Android software.
In a recent work situation a security vulnerability was discovered with the Samsung Galaxy S3. A company was clearly an easy target to have private data extracted from their phones, and because of the slow process of Android updates coming from the carrier rather than from Google, this company was forced work despite a security hole until the new version of android was pushed through their carrier. Eventually the problem was remedied, but not until two months after the security hole was first discovered. This is why it is so critical for updates to come straight from android rather than from Verizon or AT&T.