I have used micro SD cards for years. They are still the most convenient external storage solution for smartphones and other small electronic cameras. A micro SD card like this one that comes with an SD adapter is also a great way to transfer your files from the card to a proper computer.
I've gotten several of these Transcend micro SD cards, and have used for several purposes. One of them I use with the included adapter inside my Canon DSLR camera. It's good way of having the flexibility of directly transferring the photos you take either to the computer or to an Android phone/tablet. The speed of the card is pretty good for my purposes, including shooting HD video. It seems to be indeed a proper Class 10 SD card.
The second card I use with my Nextbook Windows 8.1 tablet. It's a very good way of expanding the limited internal storage that came with my tablet. The card was easy to install, and it worked without a flaw with the Nextbook.
I was also impressed with the packaging for this card. It is incredibly easy to open, and the inside packaging doubles as a storage case for the card and the adapter. This comes in really handy - micro SD cards are incredibly easy to lose.