Buying the cheapest ram isn't always cheaper. Take OCZ gold for instance, I bought 6gb of that and had to return it. Yet every time I buy Corsair the ram runs just fine and have yet to see a bad stick, well worth an extra couple dollars.
I've never once had a problem with their memory. Not having to send stuff back and having what you've just bought work... like it's supposed to is reason enough for me to think that Corsair's product kicks ass.