I have a suspicion that a lot of these cards are all made at the same factory and then badged as whatever according to orders. The more reliable cards seem to be made at their own factory where quality control would be better. It seems most of the cards that fail are the cheaper brands where QC might not be so tight. Having said that, considering the amount of cards sold there isn't that many that fail whoever makes them. You just don't want to be the one who has a card failure at a critical point.
I've had a couple of SD cards fail, one Sandisk and one 'no name' brand, and they were years ago before the SDHC cards were released. I must of had 50+ SD cards altogether so not a great failure rate. The 'no name' card failed because the lock button came loose and went inside the card and I didn't want to risk it coming out in the camera.
I've got mostly Duracell cards now, 4 16Gb CF cards, 4 16Gb SDHC, 4 8Gb SDHC and 1 each Sandisk 4Gb CF and Verbatim 16Gb CF and I never really use the last 2. The Duracell cards are excellent and very reliable.
