I've looked at these game branded versions before and dismissed them "never really read the details". Was about to purchase the standard 12 month version when I noticed the price had increased overnight, so took another look at these versions and was surprised to find that it is exactly the same package, still sold by Amazon, only cheaper, with the added bonus of 1 extra month.
So simple to install, just pay for your purchase, click on the button marked "view online code" and install the code into your Xbox account via your controller while your Xbox is connected to the internet and there you have it. 13 months membership a good bit cheaper than you'll get it if you renew via Microsoft. No need to worry about your credit card details being hacked over at Microsoft and even cheaper than Amazon's standard 12 month green card packaged "standard" version.