So you're looking at buying this, which means you're looking for the memory card and the reader.
Given the current Amazon prices are ~$5 different between the model with the card reader and just the card, this means the card reader costs you approximately $5, right?
Well, you get what you pay for.
The card itself is fast, both in writing from a Canon XSi DSLR camera and in reading from the included card reader. The capacity is 8 GB (less in actual use thanks to formatting the device). I can take the quoted fastest frames per second (3.5 fps) with this card, unlike the generic 2 GB SD card I have. The Class 6 speed really seems to help.
Now the card reader itself... it's VERY cheaply built. It doesn't feel like it will break if you drop it, but it doesn't seem like it would take much to damage it either. The memory card sticks out of the reader which is a blessing or a curse depending on how you look at it. It's easy to remove the card from the reader. It just takes some lining up on your part to ensure the card is inserted correctly.
For a $5 premium? I don't care if the reader is cheaply built. It WORKS and it is cheap. And that's enough for me.