Doesn't come down to what is better, They are both good. One might have one tech that the other doesn't. Radeon is the cheapest option then geforce, yet seen radeon cards can beat an good geforce card.
My vote goes to GEforce! since I always used it and they give that more extra power, overclocking and more performance and also just little more costly
Its hard to say which one is better because how do you define better? A comparison test would be required to work out which provide better results for gaming. However, I use GeForce and prefer it over Radeon.
I have only ever used radeon, never once had a geforce as its very $$$ especially where i live, and all the games i wanted to run was smooth, Just go with what works for you and not worry about fan boys
I've only used cards from amd since 2007 and haven't had a single card die on me yet, my oldest one (a 5670) is still in use in my nephews rig that I gave him and I've been using a radeon hd 7950 since late 2012 and it's still going strong.