That's interesting, but you're probably right. The SDXC cards seem a bit harder to get hold of and very expensive. I've had 3 SDHC cards and none of them have worked right. Easier with a pen drive anyway - I can use it in TV, PC and tablet. I don't know why I didn't buy one in the first place.
I've only spent about £15 in total on 3 micro SD cards, but it does prove that you only get what you pay for.