When you loose images that you could have had in a second card, images that are critical to your survival as a tog., then you won't have the question as to the wisdom of my purchase (I dare say).
I've usually found the errors to be the reader. Sometimes reseating the card fixes everything. Sometimes rebooting and reinitializing the reader fixes everything. There's no way to know in your case, just my experience.
Glad you got em off, i lost half a game and rescue pro did nothing
turns out my 3 cards were a bad batch but sandisk is replacing them, id give them a call if the problem comes up again