I just now tested this out with a 4GB file copy in Linux, and it works perfectly.
It is able to move the data to the level I would expect for my superfast 16GB class 10 Adata SDHC card.
The reader also has a neat little retainer that keeps the cap that covers the SDHC card attached to the reader itself when it is opened.
A word to those unfamiliar with these retainers is that you need to be careful the first time you pull that cap off to insert your SD card, or you will snap its retaining clips right off.
Just as long as you exercise a little care in pulling that cap rearward, it will stay put as you insert your card, then snap it back over it.
I like the retainer, since it ensures that little cap does not get separated from the reader, and the reader is well built, more solid than most other similar sized readers, with the cap that covers the USB plug having a very good snap that keeps it in place.
Another small matter with this reader that makes it appeal to me is that it works unusually well with Linux, with even the LED on it turning off when I give the eject command to the reader.
Trust me when I say that a lot of SD card readers work poorly with Linux, with some failing in mid-copy, not having their LED shut down upon the eject command, and pitifully slow I/O.
This card reader is one of the best out there, and I will get more of them if I purchase more SDHC cards.