I've actually heard the same thing: A-Data cards failing mechanically, but not electrically (well, not more than any other brand). So it depends how you're going to use it. If it's going to stay in your tablet, rather than going through insert/remove/put-in-pocket-and-sit-on cycles, the A-data should be fine. (Though truth be told, I've got one 4GB A-data card which I actually swap around more than any other card, and it's holding up fine. I never carry it loose, though; it's always in one device or another.)

But one thing's for sure: I'd definitely go for Class 6, of whatever brand, if you plan on cloning to it. Transferring large media collections (the only other reason I know for a big card) is also a good argument for Class 6, but can be mitigated by setting it to transfer overnight. But if you clone, boot times and load times are with you always. Also, whether you clone or not, if you use swap on the card, faster is better. (OTOH, you could use a slow, big card for storage, and put the cloned system and swap on a 2-4GB Class 6 if the cost is a major factor.)