Wrong! Higher class logic doesn't work with Android.
If you want performance and speed then you would need to go for Class 4 and not class 6 & above.
There are a lot of articles even on XDA that explains why a higher class card is bad for android.
If you really want to go for a higher class card then you should try Sandisk Extreme versions. They cost much more than the normal versions of there cards.
I am using a 32GB Sandisk Class 4 normal card(though I feel a 16GB extreme would have been good as well). And feel no lag with that.
Lengthy Explanation: You must understand that Android creates a lot of small files(KB's) which are accesed by the OS more often than bigger files. So, while transfering a single 200MB video file would be faster with a Higher Class card. Transfering the same amount of 300 distinct files would take much more time with a higher class card for the simple reason that it fills the buffers before starting the procedure. While a lower class card would begin the transfer process almost instantly. So, it would have already finished transfering a small file while the higher class is only begining to transfer that data. Also, note that saving videos and pics from the camera directly to higher SD card would be much more laggy as compared to a Class 4 card.
So, go for a Class 4 Sandisk card for using your mobile to it's optimum level. If you want the best then try to get the higher class Extreme Sandisk SD versions which are able to transfer small files with the same efficency as the bigger files.
