I have had 3 Transcend 8 GB (Class 6) cards die within the past 2 months. One was understandable; it had probably reached its effective read-write limit, as I used it for daily backups, and it failed softly, with only some of the files corrupted.
The other 2 cards failed completely--None of the 5 SD card readers I have in-house, including the camera that recorded them, detect anything other than the physical presence of the card--no electronic presence at all. They were about a year old and had had relatively light use in terms of reading and re-writing.
Elsewhere on the 'net, people report failures of far more expensive cards after only a few days, and there is no consensus that Transcend is any better or worse than premium cards. I simply offer my experience as one more piece of anecdotal data. Our collective experience also underlines the fact that one had better back up the data on *any* flash-memory card as quickly as possible.
In terms of recovering the cost of the card itself, most vendors will replace defective cards for free; but of course that does you little good if you have lost the visual record of a once-in-a-lifetime trip.