Which compact flash card is better?

They are both Sandisk 8G 30mb/s cards. One is more expensive than the other but I cant figure out why. The pictures are different in the links only with one having the trademark logos and one not having them. The cheaper one is a class 6 card but it doesn't say what the other one is. I'm looking at walmart.com because I'm having my mom run out for it soon. Here's the cheaper one and the more expensive one. I would be using this with a 7D so it needs to be a faster one, would be using the 8 frame rate a lot as I like to do sports.