SD Cards. What class and from whom to buy them?

view story

http://forums.androidcentral.com – So I want more space, basically only for music on my S3. Do classes, then, really matter? If so, then what class should I look for? And lastly, who do I buy the sd card from? (ie. samsung because that's the brand of phone, maybe theyre more compatible? or sandisk? or what?) (HowTos)