I had a bad experience with my (older) 8GB Transcend SDHC class 2 card earlier last year when i went Europe for a holiday where a few of my files ended up corrupted. Lucky for me i shoot raw as well, so when it happened, it hits either one, and the other preserved. Although it did not happen very often, but to me it was bad enough. I switched to Sandisk and never gotten the problem since.
While i think it is probably a bad sample. but just food for thought for everyone.
I am in no way affiliated to any card makers as well.