PREVIOUSLY I was unaware was the little number "6" [DENOTING CLASS] meant something (Transcend I believe the highest, class 6)
There are different speed grades available, measured the same as CD-ROMs, in multiples of 150 kB/s (1x = 150 kB/s
SD Cards and SDHC Cards have Speed Class Ratings defined by the SD Association. The SD Speed Class Ratings specify the following minimum write speeds based on "the best fragmented state where no memory unit is occupied"
Class 2: 2 MB/s - 13x
Class 4: 4 MB/s - 26x
Class 6: 6 MB/s - 40x
So just like USB flash drives basic & premium model transfer times vary 'wildly', with SD cards not so much due to specified class rating.
Simple maths shows you a "class 6" is 3 times faster than a "class 2" and 1.5 times faster than "class 4".
Finally whilst I do not know the details of this item being supplied to the other reviewers without adapter, I emailed my seller before hand just to confirm, MINE WAS SUPPLIED WITH ADAPTER and having it makes a difference!
I wish to point out that the class ratings are seen more in MICRO SDHC cards ie cards above 4GB, and NOT so much on the MicroSD cards <4Gb.
TRANSCEND MICRO SDHC ALL APPEAR TO BE CLASS 6, So that should also apply to their MICROSD cards. I hope I have not confused anyone