They do specifically state that not all cards will work and only ones purchased through them will be guaranteed to work. It isn't actually thinkware that are to blame on this one, the SDCard manufactures use all sorts of tricks to increase the read and write speed of a card, some of these tricks are stored inside of a protected area of the card which you can't access, think of it as something similar to prefetch in windows but these "improvements" can have a negative aspect on stability or other types of read write operations,
so on the face of it the card may well be able to pump out blistering speeds in sequential writes or reads but its random rights and reads might be stunted. The most important numbers are the IOPS, input output operations per second when dealing with lots of different read write operations.
My PNY card had issues, in terms of spec its was almost the same in terms of sequential read write operations, even in writing random tests it was similar, it was however clobbered in random read tests and IOPS which initially led to the card error message.
Windows format doesn't do a good job at clearing the card completely and doesn't make any effort to clear the secure area at all, SDformatter however does, so after doing that a couple of times on PNY, then a few formats on the device its self, it seems to work just fine.
I happen to have a card kicking around to use so I'm not to bothered, but if I were to buy one id be doing some extensive research.
Bare in mind, even buying the same brand and model of SD card might lead to different results depending on components used and where it was made, its a bit of a mine field if I'm honest and is very much down to luck of the draw, all you can do is try even up the odds a bit by making sure you know what your buying.
