I am choosing Android based on I get better bang for buck, get bigger storage (microSD), and have access to its internal storage (like Windows).
Perhaps my primary reason of the above is Price. I can't afford Apple pricing.
What is your primary reason?
Edit: interesting result. I thought the highest vote would be on Price or Value.
Torrenting on phone and watching TV right away without the need to transfer is my main reason.
Costs does matter but the flexibility of android is too good.
That said, I'd never recommend android to my parents and without going into the usual details - credit where credit is due. Android users who don't understand this need to step out of their own shoes for a moment.
Edit: discounting the costs of iPhones, for the majority of people who literally all they do is text, Google random things and social media, I don't feel android does these things better than Apple.*
*I have not used an iPhone since my 3gs