Nazosan
I noticed a long time ago that even when not really running at very fast speeds (and I'm mostly talking about reading as mostly it was playing music and video files) this card seems to get fairly warm.  After a while -- pretty much just outside the point at which I could RMA it -- it started randomly disconnecting.  At first I thought it was my phone though I had no clue why it would ever do such a thing, so I wouldn't have sent it in at that point anyway.  It always seemed to be fine when I plugged it into my computer.  Over time it got worse and worse and I would have to remove and put it back in quite a few times to get it to finally work.  Eventually it started doing this on the computer too and that's when I realized something was fishy.  I switched to another card in my phone and the problems went away.  On the other hand, this one stopped working completely a bit later even in the computer.Maybe I just got a bad one, but right now I'd rather get a different one instead if I were to buy a new one.